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Italian pilot Lt Giulo Gavoti dropped grenades on Turkish troops below. Gavoti flew a Bleriot XI
The Zeppelin Menace ↑
In the early months of the war, a number of high-ranking German naval and military personnel were in favour of launching an aerial campaign against Britain. One of the leading advocates, Konteradmiral Paul Behncke (1866-1937), believed that bombing London, its docks, and the Admiralty building in Whitehall would cause panic in the civilian population, which “may possibly render it doubtful that the war can be continued.”  Wilhelm II, German Emperor (1859-1941) however, showed a marked reluctance to sanction air raids, particularly on London.
The first bomb to fall on British soil, dropped by a seaplane, landed in Dover on 24 December 1914. The Kaiser, however, only gave his conditional approval for Zeppelin raids (Germany actually used both Zeppelin and Schütte-Lanz airships) to commence on 10 January 1915. London remained excluded as a target until May, with the first raid on the capital taking place on 31 May 1915.
Over the course of 1915 and 1916, German raids reached Britain on fifty-nine occasions (forty-two by airship, seventeen by aeroplane). During this period, airships attacked London eight times, in addition to a raid made by a single aeroplane. On the night of 8/9 September 1915 a Zeppelin attack on the capital caused material damage estimated at £530,000, the most of any single air raid.
Until the summer of 1916 Britain’s defences struggled to offer an effective response. Then, following the introduction of new explosive and incendiary ammunition, the advantage swung in favour of the British pilots: they now had an effective means of igniting the Zeppelin’s hydrogen.
Dawn Of Destruction – History’s First Air Raid.
“Today I have decided to try to throw bombs from the aeroplane. It is the first time that we will try this and if I succeed, I will be really pleased to be the first person to do it.”
2 nd Lieutenant Giulio Gavotti, Italian Air Force.
It is dawn at an Italian airstrip somewhere in Cyrenaica, what we now call northern Libya. After a scanty breakfast and the usual pre-flight checks Sottoteniente Giulio Gavotti fires up the engine of his ‘Etrich-Taube’ monoplane (barely more than a powered glider) for a standard flight over enemy territory during the Italo-Turkish War.
But this will not be a standard flight at all. Gavotti has resolved to attempt something never before seen or performed in flying history. Gavotti intends to find enemy targets and deliver history’s first-ever airstrike by dropping several ‘Cipolli’ anti-personnel grenades onto whatever targets of opportunity present themselves. To do this, Gavotti will have to fly his underpowered and sluggish aircraft one-handed while rummaging in a bag for his grenades, pull their pins with his teeth, swap each grenade and the control column from one hand to the other and then drop the grenades over the side onto his targets. Assuming he isn’t hit by ground fire, doesn’t drop a grenade inside his cockpit, his engine doesn’t break down and he doesn’t run into bad weather, Giulio Gavotti will take his place in the Pantheon of pilots as having flown history’s very first bombing raid.
History’s first aerial bombing raid.
His weapons, by today’s standards, are pitiful, a leather satchel containing four ‘Cipolli’ grenades each weighing four pounds and about the size of grapefruit. His targets are far too large for such weapons, with the benefit of a century’s hindsight. He doesn’t even cause any casualties, not a single enemy soldier is dead or wounded. But within its context, its time and place, his actions are momentous. From the First World War (involving the first destruction of an entire army entirely using air power) to the Second World War (Hamburg, Cologne, Coventry, Dresden, Hiroshima and Nagasaki) via Vietnam’s ‘Linebacker’ raids and the ‘Shock and awe’ tactics employed against Iraq, all flowed from Giulio Gavotti’s one-man airstrike.
The Etrich-Taube, history’s first bomber.
Gavotti’s aircratf wasn’t exatly a Stealh Bomber, either. The Etrich-Taube could carry two airmen (Gavotti’s bombing raid was a solo flight to make room forhis bombs). It was just under ten metres long with a 14.3-metre wingspan, was 3.2 metres high and had a top speed of 62mph provided by a Mercedes engine that was outclassed even by some racing cars of the period. Hardly what you’d call a thoroughbred by today’s standards but, again, this has to be put into context as this was less than a decade after the Wright brothers made the first-ever manned, powered flight at Kitty Hawk in 1903. In 1906 they gave their first European demonstration flight at Le Mans along a stretch of road nowadays known as the Mulsanne Straight’ as it form part of the Le Mans 24 Hours circuit. No doubt, Gavotti might have preferred to be at the controls of a B-52 or a Lancaster but they simply didn’t exist.
A 4-pound ‘Cipelli’ anti-personnel bomb. Not much, but enough for the first air raid.
His cargo wasn’t exactly on a par with later raids such as those of the Luftwaffe or RAF Bomber Command, either. Just four ‘Cipolli’ anti-personnel grenades each weighing four pounds and about the size of a grapefruit. Hardly Dresden or Hiroshima, but certainly we have to put this into the same context. As nobody had performed an aerial bombing raid before and nobody happened to have a crystal ball, nobody could have predicted exactly how far (or how quickly) aerial combat, bombing and bombers could (or would) advance, especially not when forged into a full-scale armed force during the crucible of the First World War.
Gavotti first targeted the Jaguiara Oasis (nowadays submerged beneath downtown Tripoli). He flew over at 600 feet to avoid ground fire as, while he didn’t know if he could kill enemy troops, he had a reasonable idea that their guns could kill him if he strayed low enough to make an easy target. With three of his four bombs dropped successfully on the oasis he turned to his secondary target, the Ain-Zara military encampment. His fourth and last bomb fell successfully and detonated, without any of the four causing a single casualty. Still, it was a first in world military history and the precursor to infinitely worse death and destruction.
And it wasn’t Gavotti’s only first, either. On March 20, 1912 he also performed the first aerial reconaissance by night. Other pilots (Gavotti included) had successfully performed and survived aerial recon by day, but nobody had even attempted it by night. It was considered just too dangerous until Gavotti proved the doubters wrong.
Bomb in pocket
He had imagined that he would only be flying reconnaissance missions there, but then realised that more was required of him.
"Today two boxes full of bombs arrived," he wrote in a letter to his father, sent from Naples. "We are expected to throw them from our planes."
"It is very strange that none of us have been told about this, and that we haven't received any instruction from our superiors. So we are taking the bombs on board with the greatest precaution.
"It will be very interesting to try them on the Turks."
By bringing aircraft to the battlefront, the Italians were doing something new.
This was only eight years after the pioneering Wright brothers in America had managed the first, short flight. Flying was still in its infancy.
"As soon as the weather is clear, I head to the camp to take my plane out," the Gavotti wrote.
"Near the seat, I have fixed a little leather case with padding inside. I have laid the bombs in it very carefully. These are small round bombs - weighing about a kilo-and-a-half each. I put three in the case and another one in the front pocket of my jacket."
Gavotti took off and headed for Ain Zara. It is now a town just east of Tripoli, but at the time he described it as a small oasis.
There he would have expected to find Arab fighters and Turkish troops that were allied in the fight against the Italian invasion.
List of air operations during the Battle of Europe
This World War II timeline of European Air Operations lists notable military events in the skies of the European Theater of Operations of World War II from the Invasion of Poland to Victory in Europe Day. The list includes combined arms operations, defensive anti-aircraft warfare, and encompasses areas within the territorial waters of belligerent European states. [note 1]
German OKW V-2 forces 
Polish Air Force
French Air Force
United Kingdom Royal Air Force 
Italian Regia Aeronautica
Soviet Union Red Army Air Force
Finnish Air Force
Royal Canadian Air Force
Romanian Air Force
Royal Hungarian Air Force
United States Army Air Forces 
United States Artillery Observers
Royal Bulgarian Air Force
1 September: At 4:40am the Luftwaffe starts World War II with the terror bombing of the Polish city of Wieluń. At 8:00am German ground forces cross the Polish border launching the invasion of Poland.
1 September: The Luftwaffe begins Operation Wasserkante as part of the invasion of Poland. The first air attacks against Warsaw start.
2 September: Single PZL.23B of the 21st Squadron of Polish Air Force bombs a factory in Ohlau. The attack represented the first Allied bombing raid to be conducted against a target in territory within the Third Reich.
3 September: Flying officer Andrew McPherson is the first Royal Air Force pilot to cross the German coast after the United Kingdom declared war on Nazi Germany. Flying a Bristol Blenheim from 139 Squadron, his mission is to identify German maritime targets around Wilhelmshaven. 
3 September: The RAF launches its first raid of the war over Germany territory. Eighteen Handley Page Hampdens and nine Vickers Wellingtons are sent to attack the German warships moored at the Wilhelmshaven naval base. However poor visibility prevents the bombers from finding any targets before nightfall so they return. 
4 September: The RAF launches another bombing operation against German shipping. Fourteen Wellingtons from 9 and 149 Squadrons attack Brunsbuttel and 15 Bristol Blenheims from 107 and 110 Squadrons raid Wilhelmshaven bay. Five Blenheims and three Vickers Wellingtons are shot down through a combination of Messerschmitt Bf 109s and flak. They become the first British aircraft casualties on the Western Front. 
4 September: The first British airman to be taken prisoner was Sergeant George Booth, a RAF Observer from 107 Squadron. He was captured after his Bristol Blenheim was shot down over the German coast. 
13 September: The Bombing of Frampol was the war's first area bombardment
20 September: The first recorded RAF "kill" of the Second World War is claimed by air observer Sergeant F Letchford aboard a Fairey Battle flown by Flying Officer LH Baker from 88 Squadron. 
20 September: The first recorded kill of the French Armee de l'Air is credited to Sergeant André-Armand Legrand, flying a Curtis H75A-1 in the Groupe de Chasse II/5 La Fayette, for downing a Messerschmitt Bf 109E of the Luftwaffe 3/JG 53 over Überherrn. 
27 September: The Luftwaffe ceases its bombing campaign against Warsaw after its Polish garrison surrenders to German forces. Approximately 1,150 sorties were flown by a wide variety of aircraft, including obsolete Junkers Ju 52/3m bombers. 
30 November: The Winter War between Soviet Union and Finland starts. Three hours after the Red Army had crossed the border and started the Winter War, Helsinki is bombed. Throughout the war, the Soviet Air Force has the air superiority and several cities in Finland are targeted.
18 December: The first use of radar for defence (an "experimental Freya radar") gave warning of RAF bombers near the German Bight as they made an attack on Wilhelmshaven.  : 20 However the German fighters were not permitted to intercept until visual confirmation was made - the bombers were attacked after they had dropped their bombs.
13 May: Luftflotte 3 (supported by Luftflotte 2) in the Battle of France executed the heaviest air bombardment to date (300 sorties)--the most intense by World War II Luftwaffe.
14 May: Under cover of Adolf Galland's air wing and after dummy paratroopers were airdropped (imitating battle noises after landing), Fort Eben-Emael was taken by glider troops during the Battle of Belgium.  : 3
15 May: A kill shared by French pilot Rene Mouchotte and Englishman Jack Charles becomes the 1,000th victim of RAF Biggin Hill fighters--Vickers threw a "fabulous party"
15 May: The RAF lost the 100th of its France-based bombers. In 72 hours, it had lost half of its offensive force. 
15/16 May: In the 1st large-scale World War II strategic bombing  : 53 and the 1st attack on the German "backcountry", just 24 of 96 dispatched bombers found the Ruhr Area power stations and refineries. 
19 May: French fighters strafed advanced columns of Operation Abendsegen  : 4
27 May 1940: Heinkels bombarded the Dunkirk perimeter followed by Stukas and Dorniers: opposition included the "first major encounter" by Spitfires of No. 74 Squadron RAF.  : 71
27/28 May: A No. 10 Squadron RAF Armstrong Whitworth Whitley tail gunner was the first in the RAF to down a German fighter.
2 June: Robert Stanford Tuck led a wing of Spitfires from RAF Martlesham Heath, the first "big formation" of the war, against eith Heinkel He IIIs and about 25 Messerschmitt Bf 109s over the Calais area.  : 108
3 June: Operation Paula was Nazi Germany's "single attempt at strategic air warfare during the French campaign."  : 7
7-8 June: French Air Force raid is the first air raid against Berlin. [ citation needed ]
June 11/12: First British bombing of Italy with a raid on Turin.  [ specify ]
26 June: The RAF Advanced Air Striking Force disbanded after beginning operations in France in May
24 July: Ferrying of Luftwaffe aircraft to the Channel Coast ended the first phase of the Battle of Britain  : 15
9 August: The Birmingham Blitz began and (along with Hull Blitz) became the basis for the RAF dehousing bombing policy in 1942.
7 September: The Blitz bombing of Britain began with 57 nights of air raids
8 September: Three Dornier 17 bombers are downed by a single shot from a "Territorial gun crew" near Farnington.  : 129
9 September: A bombing raid on Tel Aviv caused 137 deaths. 
19 October: Four SM.82 bombers attacked American-operated oil refineries in the British Protectorate of Bahrain, damaging the local refineries.  The raid also struck Dhahran in Saudi Arabia, but causing little damage. 
15 September: In a single day, the Luftwaffe loses 60 aircraft over England during the Battle of Britain  : 68
14 November: In the Coventry Blitz Luftwaffe aircraft cause significant, and infamous, damage to Coventry, killing nearly 700 people and destroying Coventry Cathedral.
30 November: The second phase of The Blitz began against British industrial and port cities
21 January: As revenge for the British raids on Berlin, Germany started the Baby Blitz (planned since 27 November).  : 396
10 February : Operation Colossus, the first British paratrooper raid, blew up a strategic aqueduct in Calitri southern Italy. [ specify ]
31 March/1 April: A bombing raid on Emden is the first use of the 4,000 lb (1,800 kg) HC "cookie" blockbuster bomb
15 April: The Belfast Blitz kills 1000, the greatest loss of British lives outside London from a night raid.
10 May: The longest blitz air raid on london killing 2324 people and 11,000 houses.
22 June - 3 July: In the opening phase of Operation Barbarossa, the Luftwaffe achieved air superiority by destroying some 2,000 Soviet aircraft, at a loss of only 35 aircraft (of which 15 were non-combat-related).
8 July First use of the Boeing B-17 Flying Fortress in Europe against Wilhelmshaven
8–9 August: The Red Army Air Force began a limited bombing offensive with a raid on Berlin. 
15 August: Robert Stanford Tuck led the first air mission by fighters based in eastern England against enemy-occupied territories in a "Rhubarb" sweep of the Netherlands for ground targets by two Hawker Hurricanes .  : 215–219
18 August: A 18 Squadron Blenheim dropped an artificial leg over France for captured Wing Commander Douglas Bader. 
7/8 September: The heaviest RAF raid on Berlin to date, with 197 bombers, with 15 bombers lost. 
7 November: A large raid on Berlin lost 20 bombers and caused little damage. The head of Bomber Command, Richard Peirse, was subsequently replaced in February 1942 by Arthur Harris.
7/8 December: 251 bombers target Aachen and Brest—the Brest attack was the first operational use of the Oboe navigation system
18 December: Blenheim aircraft conducted the first night intruder attack, successfully striking Soesterberg airfield in the Netherlands with bombs and attacking two German bombers in the air with guns
16 February: The first regular operations with the American Douglas Boston bomber were conducted.
8/9 March: The first city raid following 14 February Area bombing directive bombed Essen.
13/14 March: Gee radio navigation was first used during a bombing of Cologne. 
25/26 March: In the largest force (254 aircraft) sent to a single target to date, bombers of an Essen mission were drawn off by decoy fire from Rheinberg. [ specify ]
28/29 March: The Bombing of Lübeck was the 1st major success for RAF Bomber Command against a German city.
8/9 April: The largest force to date (272 aircraft) bomb Hamburg.
17 April: The Augsburg Raid is the first to attempt low-level daylight bombing for accuracy - in this case against the factory producing engines for U-boats. Half of the 12 bombers were shot down for little damage caused.
23–29 April: The first period of the Baedeker Blitz bomb the provincial cities of Exeter, Bath, Norwich, and York.
23–27 April: Bombing of Rostock. 
30 May: The first use of the bomber stream and the first British large scale operation, as part of Operation Millennium the first "Thousand Bomber" raid is sent against Cologne, Germany. Of the 1,047 aircraft sent, nearly 900 bombed the target area - the whole raid passing over in 90 minutes.
11–12 June: First American daylight raid over European soil, against petroleum wells in Ploiești, Romania, along with objectives in Bulgaria, the first stages of American Bombing offensive. 
25/26 June: The third "Thousand bomber" raid bombs Bremen, a new record of RAF Bomber Command losses (48 of 1,067 aircraft).
4 July: The first American bombing mission over enemy-occupied territory in Europe used 20 Boston bombers (plus 6 RAF-crewed Bostons) to attack the Alkmaar, Hammsted, and Valkenburg airfields --  : 106 only two reached the target area (two shot down, the others heavily damaged).  : 111
14 August: First German warplane downed by the USAAF. A German Focke-Wulf Fw 200 Condor reconnaissance-bomber is shot down by two US fighter pilots, flying a Curtiss P-40 Warhawk and a Lockheed P-38 Lightning, off the coast of Reykjavík, Iceland. All six German airmen are killed as the plane explodes and goes into the sea. 
15 August: 82nd Airborne is the first US airborne division. (the first combat jumps were 8 November 1942 by the 509th Parachute Battalion in the North Africa Operation Torch).  : 106,107
17 August: 12 B-17s of the 97 BG (including one with Eaker aboard) escorted by RAF Spitfires bombed the Sotteville railyard 3 miles (4.8 km) South of Rouen, France, in the "first combat action" of the Eighth Air Force and the first B-17 bombing of Europe.
19 August: 22 B-17's drop 34 tons of bombs on Abbeville/Drucat A/F in France causing extensive damage.
20 August: 11 of 12 B-17's bomb Amiens/Longeau Marshilling Yard, France at 1801 hours without loss.
21 August: 12 B-17's are dispatched to bomb the shipyards in Rotterdam, Netherlands but is aborted due to an attack by Bf 109s and Fw 190s 1 bomber is damaged lack of proper coordination with the Spitfire escorts is a major factor in the failure of the mission.
24 August: 12 B-17s bomb the Ateliers et Chantiers de France shipyard in Dunkirk.
2/3 September: [ specify ] The first use of the 8,000 lb (3,600 kg) High Capacity bomb (Blockbuster bomb) was against Karlsruhe.  : 1441
9 October: First Eighth Air Force B-24 Bombing raid, bombed Industrial Plants at Lille, France.
24 October: 88 aircraft use independent routes over France to rendezvous at Lake Annecy for a daylight raid on Milan.
22 December: An unsuccessful Bombing of Frankfurt am Main in World War II was the first use of the Master Bomber tactic. [ citation needed ]
27 January: The first World War II US mission flown against the German homeland bombs Kriegsmarine submarine pens in Wilhelmshaven.  : 107
13 April: The Eighth Air Force's largest mission to date (115 B-17s) destroys half of the Focke-Wulf factory buildings in Bremen
16/17 April: A force of 327 Lancasters and Halifaxes set out to destroy the Skoda arms factory at Plzeň, in German occupied Czechoslovakia. 271 aircraft raided Mannheim as a diversion the same night. The force mistook the mental hospital near Dobřany to be the factory at Plzeň. The raid sustained the heaviest losses until that point in the air war. 
3 May Ramrod 16 bombing of steelworks at IJmuiden
5 May: Republic P-47 Thunderbolts are first used for escorting bombers.
11/12 June: The first two Operation Pointblank raids included a successful mass trial of H2S radar on Münster
13 June: The heaviest fighter attacks to date against the Eighth Air Force claim 26 B-17s bombing Bremen and Kiel U-boat facilities.
26 June: A 100 BG B-17 surrendered and then escaped.
20/21 June: Operation Bellicose targets Würzburg radar production and is the first bombing of a V-2 rocket facility.
19 July: The first Allied World War II bombing of Rome drops 800 tons of bombs on Littoro and Clampino airports, causing immense damage and 2000 deaths  : 110
24 July: After the US developed an airborne radar immune to Window, the first use of the countermeasure (40 tonnes—92 million strips) were dropped during a Hamburg bombing mission.  : 145
29 July: First use of unguided air-to-air rockets against American combat box formations of heavy bombers by JG 1 Oesau and JG 11, attacking with Bf 109Gs and Fw 190As each armed with pairs of Werfer-Granate 21 rocket ordnance, developed from the 21 cm Nebelwerfer 42 ground barrage rocket system.
1 August: Flying from North Africa Operation Tidal Wave bombs the oil refineries at Ploiești. A large number of the bombers are lost for little strategic benefit. Five Medals of Honor are awarded to American aircrew.
13 August: The first Ninth Air Force raid on Austria bombed the Wiener Neustadt Bf 109 factory
17 August: The double-strike USAAF Schweinfurt-Regensburg mission was the third shuttle bombing. British aircraft operate diversionary attacks.
17/18 August: The Operation Hydra bombing of V-2 facilities at Peenemünde began Operation Crossbow.
18 August: The counterattack against Operation Hydra included the first operational use of Schräge Musik by German fighters 
25 August: The first use of a guided anti-ship missile in wartime occurs over the Bay of Biscay, as HMS Bideford and HMS Landguard are damaged by Luftwaffe-deployed Henschel Hs 293 rocket-boosted, MCLOS-guidance glide bombs.
27 August: The first mission against a "Heavy" Crossbow site bombed the Watten V-2 rocket bunker
9 September: The Luftwaffe's KG 100 bomber wing is involved with the world's first successful use of a precision-guided munition in modern military history, through their sinking of the Italian battleship Roma, using the Fritz X armored gravity-propulsion PGM munition.
10 October: As a result of the June "surrender/escape" of a 100 BG B-17, out of the 13 B-17s of 100 BG attacking a railyard in Münster, only the B-17F of Robert Rosenthal survives to return safely to RAF Thorpe Abbotts in England.
14 October: The Second Raid on Schweinfurt (Black Thursday) resulted in 122 damaged bombers and 650 MIA/KIA.
1 November: A Combined Bomber Offensive progress report estimates that 19/19/9 German towns & cities have been virtually destroyed/severely damaged/more effectively damaged – another report claims 10% of German war potential had been destroyed 
2 November: The USAAF 12th Air Force conducted the first large Allied aerial attack against Zadar, Italy
2 November: A raid targeting the Wiener Neustadt Messerschmitt plant damaged the nearby Raxwerke V-2 rocket facility.
3 November: A Wilhelmshaven raid is the first Eighth Air Force blind-bombing mission to completely destroy the aiming point, the Eighth's first 500-plane mission, and the first use by the US of H2X radar
18/19 November: The "Battle of Berlin" aerial campaign bombing began
22/23 November: The largest force sent to bomb Berlin to date (764 aircraft) conducted the most effective World War II raid on Berlin
2 December: 100 Ju-88s bombed the port of Bari, sinking 28 ships including the American cargo ship SS John Harvey which was secretly carrying mustard gas. There were 83 military casualties from the poison. Autopsies indicated excess white blood cells, and the discovery led to the use of the gas to combat leukemia. Records were completely declassified in 1959.  : 149
5 December: B-26s of the Ninth Air Force attacked three V-1 ski sites near Ligescourt, the first No-Ball missions.  : 29
21 January: The unsuccessful Operation Steinbock, the first mass bombing of London, began the Baby Blitz
30 January: The first U.S. Intruder operation was conducted by P-47s and accurately preceded the bombers to strike fighters at Villaorba airfield.
6–27 February: The Soviet Air Force launched bombing raids against several Finnish cities. The greatest air raids once again targeted Helsinki. In this manner the USSR hoped to force Finland to break its ties with Germany and agree to a peace settlement.
19/20 February: After 14.9% of Halifaxes that crossed the coast were lost on a raid to Leipzig, Handley Page Halifax Merlin engined Mark IIs and Vs were permanently withdrawn from operations to Germany . 
20-25 February: The Argument plan was executed during Big Week and included 734 aircraft that had flown in the October 1943 Second Raid on Schweinfurt
6 March: The first large scale US attack on Berlin (some 600 bombers) dropped 1600 tons of bombs - 160-170 of 800-900 fighters are shot down  : 113
March: As Seversky predicted in 1942,  Bomber Command's 16 area bombardment raids of the Battle of Berlin (air) are unsuccessful at "substantially" reducing population and morale
March–April: Bombing stopped aircraft production at Cantiere Navale Triestino
2 June: The first US shuttle bombing mission, Operation Frantic Joe, bombed Debrecen
( German fighters subsequently attack the bombers on Soviet airfields at Focşani)
2–5 June: In preparation for Operation Overlord, Operation Cover bombed transportation and airfield targets in Northern France and "coastal defenses, mainly located in the Pas de Calais coastal area, to deceive the enemy as to the sector to be invaded".
8 June: The first use of the Azon guided bomb targeted the Melun bridge
8/9 June: The first use of Tallboy bombs pierced the roof of the Saumur railway tunnel and blocked the expected movement of a German Panzer Division
12 June: 0418 hrs: The Robot Blitz  began with a V-1 flying bomb striking Swanscombe
3 July: 74 US military personnel died in (the most for one London event) when a V-1 flying bomb struck Sloane Court East / Turks Row.
7 July:  The first of 638 modified V-1 flying bombs that reached Britain (of about 1,200) were air-launched from Heinkel He 111s ( 403 were downed) 
23/24 July: The first major raid (629 aircraft) on a German city for two months bombs Kiel
25 July: Mission 494 (1581/500 bombers/fighters) supporting Operation Cobra was the most effective saturation bombing/carpet bombing/area bombardment of the Normandy Campaign,  killing US General McNair.
26 July: The first aerial victory for a jet fighter in air combat history occurs as a Messerschmitt Me 262A-1a of Erprobungskommando 262 mortally damages a de Havilland Mosquito reconnaissance aircraft of No. 540 Squadron RAF. 
28 July: The first operational use of rocket-powered point-defense interceptors occurs as Me 163Bs of I. Gruppe/JG 400 take off from Brandis to defend against a USAAF strategic bombing raid on the Merseburg/Leuna synthetic fuel production complex. 
27 August: The RAF restarted daylight bombing of Germany (first since 12 August 1941) with an attack on the Homberg Fischer-Tropsch plant in Hamburg.  : 149
13 & 17 August: Le Havre (Mission 549) and La Pallice (Mission 559) were the targets for the first uses of the BAT guided bomb [ citation needed ]
8 September: Operation Penguin began with the first V-2 rocket launches against Paris and London
17 September: The last UK-USSR-Italy-UK shuttle bombing was completed as 72 B-17s and 59 P-51s flew from Italy without bombs to the UK 70 B-17s 57 P-51s land safely in the UK.
18 September: Stalin finally gives permission for Allied planes to use Soviet airfields. The planes conducted air drops during the Warsaw Uprising and Operation Frantic. 
1 January: Operation Bodenplatte supported the last major German offensive, Operation Nordwind, with inconclusive results.
5 January: The first mission of Operation Cornflakes begins when a mail train to Linz was bombed. Fake mailbags containing anti-Nazi propaganda were then dropped on the wreckage in the hope the letters would be unwittingly delivered by the Reichspost. The OSS dropped two million Das Neue Deutschland (German: The New Germany) propaganda newspapers during this psychological warfare operation which ended in February.  : 104
3 February: The USAAF conducts its largest raid of the war against Berlin. The attack is led by Major Robert Rosenthal of the 100th Bombardment Group (Heavy).  Judge-President of the People's Court Roland Freisler is killed in the bombing.
8-19 February: Allies begin attacks on 200 targets with 20,000 bombers and escort fighters to assist with Operation Veritable, Grenade, and Operation Clarion.  : 2059
13–15 February: The Allied Bombing of Dresden causes a firestorm that kills up to 25,000 people in the city. 
12 March: The RAF drop 4,851 tonnes of bombs on Dortmund using 1108 aircraft (748 Lancasters, 292 Halifaxes, 68 Mosquitos). Up to 98% of buildings in the city center are destroyed. It would be the heaviest raid on a single target in World War II. 
14 March: A railway viaduct at Bielefeld is destroyed by the first Grand Slam bomb to be dropped in combat by an Avro Lancaster. The attack by No. 617 Squadron RAF succeeds after 54 attacks using smaller bombs had failed. 
17 March: Adolf Hitler orders the SS to fire V-2 rockets at the Ludendorff Bridge during the Battle of Remagen. All 11 missiles miss none land closer than 500 m (1,600 ft) from the bridge. 
18 March: The largest number of Me 262s to date launch their most concentrated attacks against Allied bomber formation. Mission 894 attacking Berlin (1,329 bombers and 733 fighters) loses 13 bombers and 6 fighters. The AAF claim 25 Luftwaffe aircraft. 
22 March: Two hundred L-4 Grasshopper spotter planes each carrying one armed infantryman (instead of an observer) cross the Rhine to form a bridgehead for the US 3rd Army near Oppenheim.  : 2068 (Light aviation became a major part of the US Army's Field Artillery fire detection center on 4 June 1942).  : 104
29 March: At 9am, the last V-1 flying bomb to hit Britain struck a field near Datchworth a village in Hertfordshire, England. 
10 April: An Arado Ar 234, based in Nazi-occupied Denmark, conducts an unmolested reconnaissance mission over northern Scotland. It is the final Luftwaffe operation over the British Isles. 
19 April: The last RAF air operation using Grand Slam bombs in Europe takes place over Heligoland. Twenty aircraft from 617 Squadron, six with Grand Slams and the remainder with smaller Tallboy bombs, along with 16 aircraft from 9 Squadron attack the island's coastal gun-batteries. No aircraft were lost. A total of 42 Grand Slams were dropped in air operations over Germany. 
25 April: The last Eighth Air Force full-scale mission in the ETO hit the Škoda Works at Pilsen in Czechoslovakia (B-17s), while B-24s bombed rail complexes surrounding Hitler's Berchtesgaden.
2 May: A RAF mosquito from 608 squadron in Norfolk conducts the last British bombing raid of the war over Nazi Germany. It dropped a 4,000lb bomb on the naval port at Kiel. 
3 May: Typhoons of 83 Group from the 2nd Tactical Air Force attack the passenger liners Cap Arcona, Thielbek, Athen, and Deutschland moored in the Bay of Lübeck (Baltic Sea). Hundreds of concentration camp prisoners are killed on the sinking ships because intelligence they are on board is not passed on to the flight crews. 
7 May: The final European dogfight of World War II, between a small American L-4 Grasshopper liaison aircraft using personal .45 caliber pistols, and a small German liaison aircraft, a Fieseler Fi 156 Storch, forced the German aircrew to land and surrender.
- ^ abIrving, David (1964). The Mare's Nest. London: William Kimber and Co. p. 223. ISBN0-586-06368-4 . NOTE: V-2 rocket air operations were conducted by various German Army units, but operational orders were issued by a Joint Services (OKW) command.
- ^ abcd Bomber Command Campaign diary
- ^ ab
- McKillop, Jack. "Combat Chronology of the USAAF". Archived from the original on 10 June 2007 . Retrieved 25 May 2007 .
1942: JanuaryArchived 2009-02-04 at the Wayback Machine, FebruaryArchived 2009-02-11 at the Wayback Machine, MarchArchived 2009-02-11 at the Wayback Machine, AprilArchived 2009-02-11 at the Wayback Machine, MayArchived 2009-02-11 at the Wayback Machine, JuneArchived 2009-02-11 at the Wayback Machine, JulyArchived 2009-02-11 at the Wayback Machine, AugustArchived 2009-02-11 at the Wayback Machine, SeptemberArchived 2009-02-11 at the Wayback Machine, OctoberArchived 2009-02-11 at the Wayback Machine, NovemberArchived 2009-02-11 at the Wayback Machine, DecemberArchived 2009-02-11 at the Wayback Machine
1943: JanuaryArchived 2012-05-31 at the Wayback Machine, FebruaryArchived 2009-02-11 at the Wayback Machine, MarchArchived 2009-02-11 at the Wayback Machine, AprilArchived 2009-02-11 at the Wayback Machine, MayArchived 2009-02-28 at the Wayback Machine, JuneArchived 2009-02-28 at the Wayback Machine, JulyArchived 2009-02-11 at the Wayback Machine, AugustArchived 2009-02-12 at the Wayback Machine, SeptemberArchived 2009-02-11 at the Wayback Machine, OctoberArchived 2012-05-31 at the Wayback Machine, NovemberArchived 2009-02-11 at the Wayback Machine, DecemberArchived 2006-10-07 at the Wayback Machine
1944: JanuaryArchived 2009-02-11 at the Wayback Machine, FebruaryArchived 2014-12-27 at the Wayback Machine, MarchArchived 2009-02-11 at the Wayback Machine, AprilArchived 2009-02-16 at the Wayback Machine, MayArchived 2012-06-06 at the Wayback Machine, JuneArchived 2009-02-16 at the Wayback Machine, JulyArchived 2013-05-27 at the Wayback Machine, AugustArchived 2009-02-11 at the Wayback Machine, SeptemberArchived 2009-02-13 at the Wayback Machine, OctoberArchived 2010-03-07 at the Wayback Machine, NovemberArchived 2009-02-11 at the Wayback Machine, DecemberArchived 2009-02-11 at the Wayback Machine
1945: JanuaryArchived 2009-02-16 at the Wayback Machine, FebruaryArchived 2013-09-29 at the Wayback Machine, MarchArchived 2013-06-02 at the Wayback Machine, AprilArchived 2010-03-07 at the Wayback Machine, MayArchived 2010-03-07 at the Wayback Machine, JuneArchived 2009-02-11 at the Wayback Machine, JulyArchived 2010-03-07 at the Wayback Machine, AugustArchived 2009-02-11 at the Wayback Machine, SeptemberArchived 2009-02-11 at the Wayback Machine
NOTE: The Chronicles for August 13, 1944 inaccurately list the BATTY mission as an Aphrodite mission
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- Northway, B.S. (ed) (1963). A History of 107 Squadron. Tuddenham, UK: No. 107 Squadron RAF. p. 22. CS1 maint: extra text: authors list (link)
- ^88 Squadron historyArchived 24 October 2008 at the Wayback Machine, Ministry of Defence
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- Jablonski, Edward (1971). Volume 1 (Tragic Victories), Book II (The Big League). Airpower. p. 71.
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- Forrester, Larry (1973) . Fly for Your Life: The Story of R. R. Stanford Tuck, D.S.O, D.F.C. and Two Bars. Sir Max Aitken (Foreword). Garden City, New York: Nelson Doubleday. ISBN0-553-11642-8 .
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- Jones, Reginald Victor (1978). Most Secret War. Hamish Hamilton Ltd. ISBN0-2418-9746-7 .
- Michael Omer-Man (9 September 2011). "This Week in History: Italy bombs Tel Aviv". The Jerusalem Post . Retrieved 6 September 2011 .
- ^ abAir Raid! A SequelArchived 29 September 2012 at the Wayback MachineAramco World Magazine, Volume 27, Number 4, July/August 1976.
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- Seversky, Alexander P. de (1942). Victory Through Air Power. New York: Simon and Schuster. p. 145. "Destruction of enemy morale from the air can be accomplished only by precision bombing."
- ^ McBride, Gisela R.: Through my eyes: memoirs of Hitler's Berlin. Hamilton Books, 2006, page 209. 0-7618-3394-3
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- Cunliffe, Peter W. (2011). A Shaky Do: The Skoda Works Raid 16/17th April 1943. ISBN978-0955795725 .
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- Russell, Francis et al. (1981). The Secret War . World War II. Chicago: Time-Life Books Inc. p. 104, 145,149. ISBN0-16-049376-5 .
- Middlebrook, Martin (1982). The Peenemünde Raid: The Night of 17–18 August 1943. New York: Bobs-Merrill. ISBN0-672-52759-6 .
- Zaloga, Steven J. (2008) . German V-Weapon Sites 1943-45. Fortress (72). illustrated by Johnson, Hugh & Taylor, Chris. New York: Osprey Publishing Ltd. ISBN978-1-84603-247-9 .
- ^ Bomber Command diary Feb 1944
- Hill, Roderic (19 October 1948). Air Operations by Air Defence of Great Britain and Fighter Command in Connection with the German Flying Bomb and Rocket Offensives, 1944–1945.
- Collier, Basil (1976) . The Battle of the V-Weapons, 1944–1945. Yorkshire: The Emfield Press. p. 174. ISBN0-7057-0070-4 .
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- ^Stalin's Private Airfields The diplomacy surrounding the AAF mission to aid the Poles and the mission itself is extensively covered in Richard C. Lukas's The Strange Allies: The United States and Poland, 1941-1945, pp. 61-85. Warsaw Rising Museum
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- ^Dresden was a civilian town with no military significance. Why did we burn its people?Archived 21 April 2016 at the Wayback Machine By Dominic Selwood. The Telegraph, 13 February 2015
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- "Ten Tonner - video of a Grand Slam being dropped on the Bielefeld Viaduct". Movietone News/youtube.com . Retrieved 21 March 2010 .
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- Flower, Stephen (2004). Barnes Wallis' Bombs. Researched from the original records and interviews with those involved with the development and use of the bombs. Stroud: Tempus. pp. 362–64. ISBN0-7524-2987-6 .
- "Remembering the last raid on Nazi Germany". BBC News. 9 June 2015.
- Till, Major Noel O (September 1945). Report on Investigations, WO 309/1592. No. 2 War Crimes Investigation Team. From the Till report of June 1945: "The Intelligence Officer with 83 Group RAF has admitted on two occasions first to Lt H. F. Ansell of this Team (when it was confirmed by a Wing Commander present), and on a second occasion to the Investigating Officer when he was accompanied by Lt. H. F. Ansell, that a message was received on 2 May 1945 that these ships were loaded with KZ prisoners but that, although there was ample time to warn the pilots of the planes who attacked these ships on the following day, by some oversight the message was never passed on. From the facts and from the statement volunteered by the RAF Intelligence Officer, it appears that the primary responsibility for this great loss of life must fall on the British RAF personnel who failed to pass to the pilots the message they received concerning the presence of KZ prisoners on board these ships." See: Jacobs and Pool, 2004 and Till, 1945
- "Campaign Diary". Royal Air Force Bomber Command 60th Anniversary. UK Crown. Archived from the original on 6 July 2007 . Retrieved 22 March 2009 .
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- July-December 1940
- June-October 1940 (Battle of Britain), archived from the original on 6 July 2007
- January-April 1941, archived from the original on 11 October 2012
- May-August 1941, archived from the original on 3 March 2009
- September- December 1941, archived from the original on 14 October 2012
- January 1942, archived from the original on 7 December 2008
- February 1942, archived from the original on 7 June 2007
- March 1942, archived from the original on 11 June 2007
- April 1942, archived from the original on 11 June 2007
- May 1942, archived from the original on 29 September 2012
- June 1942, archived from the original on 6 July 2007
- July 1942, archived from the original on 11 June 2007
- August 1942, archived from the original on 11 June 2007
- September 1942, archived from the original on 10 June 2007 ,
- October 1942, archived from the original on 6 July 2007 ,
- November 1942, archived from the original on 6 July 2007 ,
- December 1942, archived from the original on 6 July 2007
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- February 1943, archived from the original on 21 February 2006 ,
- March 1943, archived from the original on 15 May 2007 ,
- April 1943, archived from the original on 7 June 2007 ,
- May 1943, archived from the original on 15 March 2012 ,
- June 1943, archived from the original on 21 February 2006 ,
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- August 1943, archived from the original on 11 October 2012 ,
- September 1943, archived from the original on 29 September 2004 ,
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- June 1944, archived from the original on 11 June 2007
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- September 1944, archived from the original on 14 March 2008 ,
- October 1944, archived from the original on 11 June 2007 ,
- November 1944, archived from the original on 6 June 2011
- December 1944, archived from the original on 6 June 2011
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- April 1945, archived from the original on 28 July 2012
1939 · 1940 · 1941 · 1942 · 1943 · 1944 · 1945
Sirens are sometimes integrated into a warning system that links sirens with other warning media, such as the radio and TV Emergency Alert System, NOAA Weather Radio, telephone alerting systems, Reverse 911, Cable Override, and wireless alerting systems in the United States and the National Public Alerting System, Alert Ready, in Canada. This fluid approach enhances the credibility of warnings and reduces the risk of assumed false alarms by corroborating warning messages through multiple forms of media. The Common Alerting Protocol is a technical standard for this sort of multi-system integration. 
Siren installations have many ways of being activated. Commonly used methods are dual-tone multi-frequency signaling (DTMF) or public switched telephone network (PSTN) using telephone lines, but activation can also be done via radio broadcast. This method opens up vulnerability for exploitation, but there are protections from false alarms. These sirens can also be tied into other networks such as a fire department's volunteer notification/paging system. The basics of this type of installation would consist of a device (possibly the same pager the firefighters have) connected to the controller/timer system of the siren. When a page is received, the siren is activated. [ citation needed ]
Mechanical sirens Edit
A mechanical siren uses a rotor and stator to chop an air stream, which is forced through the siren by radial vanes in the spinning rotor. An example of this type of siren is the Federal Signal 2T22, which was originally developed during the Cold War and produced from the early 1950s to the late 1980s. This particular design employs dual rotors and stators to sound each pitch. Because the sound power output of this type of siren is the same in every direction at all times, it is described as omnidirectional. The Federal 2T22 was also marketed in a 3-signal configuration known as the Federal Signal 3T22, with the capability for a "hi-lo" signal. Some sirens, like the Federal Signal Thunderbolt series, had a blower so that more air could be pumped into the siren. [ citation needed ]
While some mechanical sirens produce sound in all directions simultaneously, other designs produce sound in only one direction, while employing a rotator mechanism to turn the siren head through 360 degrees of rotation. One rare type of mechanical siren, the Federal Signal RSH-10 ("Thunderbeam"), does not rotate or produce equal sound output in all directions. It instead uses a slowly rotating angled disc below the siren which directs the siren's output throughout 360 degrees.  The chopper of this siren is taken from another one of Federal Signal's sirens, the STH-10. [ citation needed ]
The Federal Signal Thunderbolt series creates its sound by using a separate blower to force air through the rotor. Horns with an exponential profile then amplify the sound. Within the Thunderbolt product line, three different configurations were offered: the Thunderbolt 1000, a single-tone siren the Thunderbolt 1000T, a dual-tone siren and the Thunderbolt 1003, a variation of the 1000T that employs solenoid-actuated slide valves to create a "hi-lo" signal primarily used as a fire signal. Another example of a siren that has a separate blower is the Alerting Communicators of America (ACA) Hurricane. [ citation needed ]
A variation on the electromechanical siren is the pneumatic hochleistungssirene (HLS), first produced by the German firm Pintsch-Bamag and later by the German firm Hörmann. Soon afterward, Hörmann improved on the design to create the HLS 273, which did away with the massive siren head of the original in favor of a more compact head and cast aluminum exponential-profile horns. These sirens stored a reservoir of compressed air, recharged periodically by a diesel engine-driven compressor in a vault in the base of the massive siren unit. The later HLS 273 placed the large (6,000 liter) air tank underground beside the machinery vault, instead of in the mast itself as in the earlier HLS units. [ citation needed ]
Electronic sirens Edit
Electronic sirens consist of an electronic tone generator, a high-power amplifier, and a horn loudspeaker. Typically, the loudspeaker unit incorporates horn loading, causing them to be similar in appearance to some electromechanical sirens. Many of these loudspeakers incorporate a vertical array of horns to achieve pattern control in the vertical plane. Each cell of the loudspeaker horn is driven by one or more compression drivers. One type of compression driver for this type of loudspeaker handles 400 watts of electrical power and uses two doughnut-shaped permanent magnet slugs to provide magnetic flux. For siren applications, high-fidelity sound is a secondary concern to high output, and siren drivers typically produce large amounts of distortion which would not be tolerable in an audio system where fidelity is important. [ citation needed ]
As with electromechanical sirens, there are both omnidirectional and rotating categories, though Whelen Engineering produces sirens which oscillate through 360 degrees, rotating in one direction and then in the other to allow a hard-wired connection between the amplifiers and the siren drivers. These sirens can also be set to rotate any amount from 0 to 360 degrees, allowing sirens to broadcast only in certain directions. [ citation needed ]
Examples of rotating electronic siren are the Whelen Engineering Vortex, American Signal Alertronic RE1600, and Federal Signal SiraTone 408, 612, and 812 (these designs incorporate four vertically arrayed loudspeaker cells exiting into a common manifold). This horn design accomplishes pattern control in the vertical plane and focuses the output into a high-penetration beam. Examples of omnidirectional electronic sirens are the Federal Signal EOWS1212, Federal Signal Modulator series, HSS Engineering A/S, Whelen Engineering WPS2700, WPS2800, and WPS2900, ATI HPSS, and American Signal I-Force, in which compression drivers located in each cell exit into the center of the cell. The contour of each cell forms the horn. [ citation needed ]
Middle East Edit
Saudi Arabia Edit
The purpose of warnings is to notify the population of a danger that threatens their lives. Individuals must go to shelters or their homes, lock doors and windows, take appropriate protective actions, and listen through the radio and television for instructions of civil defense. 
The People's Republic of China Edit
China has sirens located in most cities and towns, particularly those located in or near disputed territories. If the state declares a state of emergency due to attacks or invasion, or when there is a very high risk of military conflict, sirens will warn the public of possible attacks or invasion. The sirens are controlled by the People's Liberation Army. [ citation needed ]
There are annual or semi-annual test runs, often occurring on commemorative dates that are associated with the Second Sino-Japanese War. For example, Nanjing annually tests air raid sirens at 10 a.m. on 13 December, followed by a moment of silence to commemorate the Nanking Massacre. There have also been some commemorative tests during the memorial periods of major disasters, such as on 19 May 2008 in memory of victims of the 2008 Sichuan Earthquake.
The air raid warning comes in 3 types: 
- Pre-raid warning: a 36-second high-tone followed by a 24-second low-tone, with three cycles per period. This warning signifies an air raid is likely about to take place.
- Raid warning: a 6-second high-tone followed by a 6-second low tone, with 15 cycles per period. This signifies that an air raid is imminent.
- Post-raid warning: a single 3-minute high-tone. When sounded, it signifies an end to the raid or a cool-down of the wartime situation.
This siren is not a "TWS." This siren system is a VisuAlert Whelen 2804.
Taiwanese civil defense sirens are erected on police stations, and commanded by the nation's Civil Defense Office ( 民防指揮管制所 ). The government issues air raid warnings, as well as tsunami warnings, through the sirens in conjunction with their own Public Warning System that utilizes 4G LTE cell signals. The Taiwanese government also holds annual air-raid drills called Wan-an drills ( 萬安演習 ) so the populace can be familiar with what to do in an air raid, given the high risk of war with its neighboring country, China.
Mumbai has around 200–250 functional sirens. The government is planning to change the system by incorporating modern wireless and digital technology in place of the present landline switching system.
In Mumbai civil defence, sirens were used during the Indo-Pakistan wars of 1965 and 1971, warning civilians about air raids by the Pakistan Air Force. At night, sirens were also used to indicate blackouts, when all lights in Mumbai were switched off. Daily tests of the sirens at 9 a.m. were recently reduced to once per month. They are controlled by the Regional Civil Defence Control Center, Mumbai, with input from Indian Defence Services. Sirens are also used to denote a minute's worth of silence on special occasions. 
Israel has more than 3,100 warning sirens. Most of the sirens in urban areas are German-made HLS sirens, models F71 and ECN3000. All the other sirens are HPSS32 models made by Acoustic Technologies (ATI). During the early 2010s, mechanical sirens were gradually phased out and replaced by electronic ones, although the mechanical ones were generally left standing. The air-raid sirens are called אזעקה (az'aka 'alarm'), and consist of a continuous ascending and descending tone. The "all clear" signal, called צפירת הרגעה (tzfirat harga'a), is a constant single-pitch sound. In recent conflicts, use of the "all clear" signal has been discontinued, as it was seen as causing unnecessary confusion and alarm. In certain regions in the south of Israel, which regularly undergo rocket attacks from Gaza, a specialized system called Red Color is used. [ citation needed ]
The "all clear" signal is used three times per year to denote a moment of silence (of one or two minutes): once on Israel's Holocaust Remembrance Day and twice on the Day of Remembrance. [ citation needed ]
Singapore currently has a network of 284 stationary sirens named the Public Warning System which warns the entire country of air raids, as well as human-made and natural disasters (except earth tremors). Singapore's sirens are tested at noon on the first day of every month. During the test, the sirens sound a light cheerful chime instead of any of the three signals. The sirens look very similar to the ECN3000 Israel version. [ citation needed ]
South Korea Edit
Nearly all towns and cities are equipped with civil defense sirens in case of natural disasters or missile attacks from North Korea. South Korea holds civil defense drills every month to prepare for such scenarios. 
Austria is fully covered with an operational air-raid siren system consisting of 8,203 devices as of 2012. They are tested weekly at noon on Saturdays (except in Vienna) with the sirenenprobe signal, a 15-second continuous tone. Every year on the first Saturday of October, the whole range of alarm signals (with the exception of the fire alert) is sounded as a system test (Zivilschutz-Probealarm) and to familiarize the population with the signals.
- Warning: a 3-minute continuous tone. People are warned of an incoming danger and advised to tune into the appropriate Ö2 regional radio station or ORF 2 for further instructions.
- General alarm: a 1-minute ascending and descending tone. Danger is imminent people should seek shelter immediately and listen to radio or TV.
- End of danger: a 1-minute continuous tone. The danger is over, and shelters can be left. Any hazards potentially encountered during normal life are announced in the media.
- Fire alert: three 15-second continuous tones separated by 7-second intervals. All firemen of volunteer fire brigades should report to their fire station immediately. This signal is being used less and less, as many fire brigades have begun to alert their members by radio. 
Belgium used to test its air raid sirens every first Thursday of the trimester (three-month period). Sirens are Sonnenburg Electronic sirens. When the air-raid sirens are tested, the message "proefsignaal" or "signal d'essai" is broadcast every time the sirens sound. There are 540 sirens all across the country.  A non-audible test was performed every day, and the last test occurred on 4 October 2018.  Afterwards, the network was decommissioned. The sirens remain around nuclear facilities, but no tests are performed.  The official recommendation is that people subscribe to BE-Alert,  a system where information is provided via SMS, e-mail or phone. 
Czech Republic Edit
The Czech Republic has around 6,000 sirens. They are tested every first Wednesday of the month. There are three warning signals, which are accompanied by a verbal message in Czech and usually with an English and German translation on electronic sirens. There is also an emergency broadcast on TV channels, maintained by Česká televize, and radio channels, maintained by Český rozhlas.
- General alert: a 140 second long fluctuating tone. The alert can be repeated up to 3 times in 3-minute intervals, and has 4 possible verbal messages:
- "Všeobecná výstraha, všeobecná výstraha, všeobecná výstraha. Sledujte vysílání Českého rozhlasu, televize a regionálních rozhlasů. Všeobecná výstraha, všeobecná výstraha, všeobecná výstraha." The danger is unspecified and people should go inside a building, close the doors and windows (the alert usually means a dangerous element may be present in the air), and turn the TV or radio to an appropriate channel to find out more.
- "Nebezpečí zátopové vlny, nebezpečí zátopové vlny. Ohrožení zátopovou vlnou. Sledujte vysílání Českého rozhlasu, televize a regionálních rozhlasů. Nebezpečí zátopové vlny, nebezpečí zátopové vlny." A flooding alert. People should turn on the radio and get away from the source of danger (usually a river).
- "Chemická havárie, chemická havárie, chemická havárie. Ohrožení únikem škodlivin. Sledujte vysílání Českého rozhlasu, televize a regionálních rozhlasů. Chemická havárie, chemická havárie, chemická havárie." There was a chemical accident. People should behave the same way as during an Obecná výstraha message.
- "Radiační havárie, radiační havárie, radiační havárie. Ohrožení únikem radioaktivních látek. Sledujte vysílání Českého rozhlasu, televize a regionálních rozhlasů. Radiační havárie, radiační havárie, radiační havárie." There was a radioactive accident. People should behave the same way as during an Obecná výstraha message.
1,078 electronic warning sirens have been installed in Denmark by HSS Engineering. The sirens are placed on the tops of buildings or on masts. This warning system makes it possible to warn the populations of all urban areas with more than 1,000 inhabitants. This means that about 80% of Denmark's population can be warned using stationary sirens. The remaining 20% are warned by mobile sirens mounted on police cars. The function of the sirens is tested every night, but does not produce any sound. Once every year, on the first Wednesday of May at 12:00, the sirens are tested with sound. 
A general alarm consists of a repeating 1-minute sound, made up of tones that ascend for 7 seconds and descend for 7 seconds. The end of danger is signaled by a 1-minute continuous tone. Warning sirens are tested on the first Monday of every month at noon. The testing alarm is shorter than the general alarm (only lasting for 7 or 14 seconds) and may be a flat tone.
In France, the emergency population warning network is called the "Réseau national d'alerte" (RNA). The system is inherited from the air raid siren network (défense passive) developed before World War II. It consists of about 4,500 electronic or electromechanical sirens placed all over France.  The system is tested each month at noon on the first Wednesday. The most common siren type is the electromechanical KM Europ 8 port single tone siren. These sirens have a very characteristic sound: a very fast wind-up and a lower pitch than most sirens (the pitch is comparable to a STL-10 on a lower frequency resulting on a lower pitch). A recording of these sirens was used in the movie Silent Hill. [ citation needed ]
In Germany, the Warnämter ('warning authorities') were closed in the 1990s after the threat of the Cold War was over, since the ability to alert the public was then considered unnecessary. As the civil defense sirens were also frequently used to alert volunteer firefighters, many sirens were sold to municipalities for a symbolic price others were dismantled. In the 2000s, it was realized that the ability to warn the public is not only necessary in cases of war, but also in events like natural disasters, chemical or nuclear accidents, or terrorist attacks. As a result, some cities like Düsseldorf and Dresden began to rebuild their warning sirens. In Hamburg, the sirens are still operational. They also warn the public during storm surges for instance, all towns in the Moselle Valley continue to operate and test their warning sirens. The majority of operational sirens in Germany are either electric-mechanical type E57 or electronic sirens.
During World War II, Berlin's air raid sirens became known by the city's residents as "Meier's trumpets" or "Meier's hunting horns" due to Luftwaffe chief Hermann Goering's boast that "If a single bomb ever falls on Berlin, you can call me Meier!". 
The Italian War Ministry began installing air raid sirens and issuing air defence regulations in 1938. Production was entrusted to La Sonora, founded in 1911 and still active today. 
During World War II, every town had a siren, and several were present in each large city. Even after the danger of bombings had ended, they were kept to provide warning in case of any threat (e.g. high water in Venice).
As of 2015, some of them still survive. For instance, as many as 34 have been located in Rome using crowdsourcing. Up until the 1980s, they underwent routine maintenance and sounded at noon. 
Additionally, the Protezione Civile (Civil Protection) operates sirens to warn the public in case of a threat to the citizen population. Protezione Civile also provides transport needs and military defence for the Government of Italy. These defence systems were put in place in the 1990s and are occasionally still used today. 
The Netherlands tests its air-raid sirens once per month, on the first Monday at noon, to keep the public aware of the system. There are about 4,200 sirens placed all across the country.  In March 2015 it was announced that, due to high maintenance costs, the sirens will be taken out of service by the end of 2020.  The government has implemented a Cell Broadcast system called NL-Alert, compliant to the mandatory European regulation EU-Alert, to replace the sirens by 2021. However, as of late 2019, the sirens will continue to be heard until another decision has been made. 
Norway has about 1,250 operational sirens (mostly Kockums air horn units rather than motorized sirens), primarily located in cities. Three different signals are used:
- Critical message, listen to radio: three periods of three signals, separated by one minute between the periods. The "critical message" signal is followed by a radio broadcast. It is used in peacetime to warn the population about major accidents, large fires and gas leaks. 
- Air raid, take cover: an intermittent signal lasting for about a minute.
- All clear: a continuous signal sounded for about 30 seconds.
The sirens are tested twice each year, at noon on the second Wednesday of January and June. As of 2014, only the '"critical message" signal is used during tests. Previously, the signal tested in June would use the "air raid" and "all clear" signals. The latter two are no longer used in peacetime.
There are also sirens in the Storfjord area in Møre og Romsdal county to warn about an avalanche from the mountain Åkerneset. These sirens are not operated by Norwegian Civil Defense department instead, they are operated by Åksnes/Tafjord Beredskap. These sirens can be found in the villages of Stranda, Tafjord, Geiranger, Hellesylt, Linge and Valldal.
In Romania, civil defense sirens have been used since the early 1930s. Originally, each street had a small siren on top of a high-rise building, which could be powered mechanically. During World War II, the sirens had a single continuous tone to warn of an air strike. 
Throughout the Cold War, larger sirens were manufactured locally and installed on various public buildings and residences.  The sirens were able to transmit a comprehensive variety of tones, each with a different meaning such as a chemical disaster, an earthquake, a flood, or an imminent air or nuclear strike each of these tones required the population to either move to higher ground or an ABC shelter. An "all clear" signal was played after the area had been deemed safe for the general public. [ citation needed ]
Since the 1990s, civil defense sirens have been replaced by electronic sirens and the procedure has been simplified. As of 2013, there are four playable tones: a natural disaster warning, an upcoming air/nuclear strike, an imminent air/nuclear strike, and an "all clear" signal. Taking shelter is no longer a legal requirement, although ABC shelters are still operational. 
In August 2017, Romanian authorities started to perform monthly defence siren tests. The first such test took place on 2 August 2017 and is scheduled to be repeated on the first Wednesday of each month, between 10:00 and 11:00 am local time. Such tests have been stopped in the wake of the COVID-19 pandemic. 
During the siege of Leningrad, the radio network carried information for the population about raids and air alerts. The famous "metronome" went down in the history of the siege of Leningrad as a cultural monument of resistance of the population.
At that time, there were more than 1 thousand loudspeakers and 400 thousand radio streams operating in the city. If there were no broadcast programs, then the metronome was broadcast with a slow rhythm of 50-55 beats per minute. The network was switched on around the clock, which allowed the population and services to be confident in the operation of the network. By order of the MPVO headquarters, the duty officer of the Central station of the radio network interrupted the broadcast of the program, turned on an electric player with a record of the alarm text. This record was supplemented by 400 electric sirens. At the end of the recording, the metronome was switched on with a rapid rhythm of 160-180 beats per minute. When the danger was over, the electric player was switched on again by order of the staff, and the alarm was sounded in the streets and houses, accompanied by the sound of fanfares.
Slovenia has 1,496 operable civil defence sirens.  Most of them are electronic sirens, although there are some mechanical ones. Civil defence sirens are mounted on fire stations, town halls, or other structures.
Three siren tones are used in the country: 
- Warning: a 2 minute long steady tone. Used to warn of the impending danger of a fire, environmental or other disaster, or high water level.
- Immediate danger: a 1 minute wailing tone. Used to warn of the danger of a major fire, flood, radiological or chemical danger, or air raid.
- All clear: a 30-second steady tone. Sounded during tests of the sirens the first Saturday of each month at noon, and at the end of an emergency for which the immediate danger signal was sounded.
The municipalities of Brežice, Krško, Sevnica, Hrastnik, and Trbovlje use a special signal for the immediate danger of an accident involving chlorine when there is a danger of chlorine leaks in the environment. The 100 second long signal consists of a 30-second wailing tone, a 40-second steady tone, and a second 30-second wailing tone. The municipalities of Muta, Vuzenica, Podvelka, Ribnica na Pohorju and Radlje ob Dravi use a 100-second signal (consisting of a 4-second wail followed by 4 seconds of silence) for the immediate danger of flash floods, used in the event of overflow or collapse of a hydroelectric dam. 
When emergencies impact two or more regions at the same time, or the whole country, people are advised to listen to the first channel of Radio Slovenia, Val 202, or watch TV Slovenia 1/TV Slovenia 2. Emergencies of a smaller extent are announced via regional radio and TV stations. 
Few sirens that were used for civil defence against bombings during the Spanish Civil War are preserved. The Guernica siren has a highly symbolic value because of the impact of the Bombing of Guernica. Barcelona City History Museum preserves one related to the Bombing of Barcelona, and another siren from civil war years is also preserved in Valencia. [ citation needed ]
The Swedish alarm system uses outdoor sirens in addition to information transmitted through radio and television. Special radio receivers are handed out to residents living near nuclear power plants. The outdoor system Viktigt meddelande till allmänheten, also known as Hesa Fredrik ('Hoarse Fredrik', alluding to the sound of the siren) to the Swedish population, consists of 4,600 sirens. These sirens were first tested in 1931, and were mounted to cars and bikes sent out by the government. The sirens can be found on tall buildings all around Sweden. They are driven by compressed air in giant tanks, but are successively being replaced by modern electronic sirens which use speakers. The emergency services are also able to send out spoken messages through the new sirens. The outdoor signals used are as follows:
- Readiness alarm (Beredskapslarm): a 5-minute pattern of 30 second tones separated by 15 second gaps. Used when an imminent danger of war is present.
- Air raid alarm (Flyglarm): a 1-minute pattern of 2 second tones separated by 2 second gaps. Sent when the threat of an air attack is imminent.
- Important public announcement, general alarm (Viktigt meddelande till allmänheten): a pattern of 7 second long tones and 14 second long gaps. People should go inside, close windows and doors, close ventilation, and listen to radio channel P4.
- All clear (Faran över): a 30-second long single tone. Used for all above signals when danger is over.
The outdoor sirens are tested four times a year on the first non-holiday Monday of March, June, September, and December at 15:00 local time. The test consists of the general alarm for 2 minutes, followed by a 90-second gap before the "all clear" is sounded.
There are usually around 15 to 20 general alarms per year. The most common cause of general alarms is fire, specially in situations that involve industries, landfills, and other facilities containing dangerous substances which can create hazardous smoke. The 2018 peak in alarms (54 that year) is attributed to the 2018 Sweden wildfires which alone caused over 20 general alarms. Other possible attributing factors could be the increased public safety awareness after the 2017 Stockholm truck attack. 
Switzerland currently has 8,500 mobile and stationary civil defense sirens, which can alert 99% of the population.  There are also 700 sirens located near dams.  Every year on the first Wednesday of February, Switzerland's sirens are tested to see if they are functioning properly. During this test, general alert sirens as well as sirens near dams are checked.  The population is informed of the test in the days leading up to the tests by radio, television, teletext, and newspapers, and the siren tests do not require the population to take any special measures. 
The tones of the different sirens are provided on the last page of all phone books as well as on the Internet.
- General alert: a 1-minute regularly ascending and descending tone, followed by a 2-minute interval of silence before repeating. The 'general alert' siren goes off when there is a possible threat to the population. The population is instructed to inform those around them to proceed inside. Once inside, people are instructed to listen to emergency broadcasts made by the broadcasting networks SRF, RTS, RSI and RSR. 
- Flood alert: 12 continuous low-pitched tones, each lasting 20 seconds. The flood alert is activated once the general siren is sounding. If heard by the population in danger zones (such as near dams), they must leave the dangerous area immediately or find shelter. 
United Kingdom Edit
During World War II, Britain had two warning tones:
These tones would be initiated by the Royal Observer Corps after spotting Luftwaffe aircraft coming toward Britain, with the help of coastal radar stations. The "red warning" would be sounded when the Royal Observer Corps spotted enemy aircraft in the immediate area. The sirens were tested periodically by emitting the tones in reverse order, with the "all clear" tone followed by the "red warning" tone. This ensured the public would not confuse a test with a real warning. [ citation needed ]
Every village, town, and city in the United Kingdom used to have a network of dual-tone sirens to warn of incoming air raids during World War II. The operation of the sirens was coordinated by a wire broadcast system via police stations. In towns and cities with a population of over 3,000, powered sirens were used, whereas in rural areas hand-operated sirens were used (which were later put to use as warnings for nuclear attack during the Cold War). At the end of the Cold War in 1992, the siren network was decommissioned, and very few remain.  These sirens, mostly built by Carter, Gents, Castle Castings, and Secomak (now Klaxon Signal Co.), have 10 and 12 ports to create a minor third interval (B ♭ and D ♭ notes) and are probably the world's most recognised World War II air raid siren sound. Recordings of British sirens are often dubbed into movies set in countries which never used this type of siren. [ citation needed ]
Around 1,200 sirens remain, mostly used to warn the public of severe flooding. They are also used for public warning near gas or nuclear power plants, nuclear submarine bases, oil refineries and chemical plants. The remaining sirens are a mix of older motor driven models (usually from World War II), such as the Carter siren manufactured by Carter's of Nelson or the "syren" manufactured by Gent's of Leicester, and Cold War and newer electronic sirens. They are tested annually between August and September. [ citation needed ]
With the advent of digital services and mobile technology, many local authorities are now retiring their siren networks in favour of contacting people by telephone. In January 2007, proposals to retire a network of sirens in Norfolk were made by the Norfolk Resilience Forum. In November 2007, residents were angered after the sirens had not sounded following a tidal surge in Walcott. In 2008, a review of the current and future role of flood warning sirens was undertaken by Norfolk County Council, after plans to retire them were halted following concerns from nearby residents.  Although some of the sirens were initially withdrawn, 40 out of the 57 were eventually temporarily reinstated.  Despite this, in July 2010 the flood warning sirens were finally retired in favour of alerting people by telephone, SMS or e-mail. After three years of consultations, the council had failed to demonstrate that refurbishing the sirens would be a worthwhile investment. 
Lincolnshire, which had one of the largest siren systems in the country,  had 46 sirens based in North Somercotes, Mablethorpe, Boston, Skegness, Spalding and Sutton Bridge, as well as inland at Louth, Horncastle, Middle Rasen and Gainsborough, the areas most at risk of being hit by floods.   Following serious flooding in the summer of 2007, investigations took place into how the flood warning system could be improved. The Environment Agency admitted that the warning system in Louth had not sounded early enough.  In April 2008, Lincolnshire County Council began to investigate the possibility of replacing the flood warning sirens with mobile phone alerts.  A council report in November 2009 described the sirens as being "outdated, in the wrong places and difficult to repair".  The sirens were eventually decommissioned in November 2011 and replaced with Floodline. 
In January 2010, 13 public warning sirens on the island of Guernsey that had first been installed in 1937 were due to be retired and replaced by text messages. This followed claims by the Home Department that the sirens had "reached the end of their useful working life". The sirens had previously been used to warn of major incidents.  From 1950 to 2010, the Civil Defence Committee took responsibility for the sirens, and had tested them annually since 9 May 1979.  Members of the public had criticised the decision,  and Deputy Janine Le Sauvage claimed that sirens were the only way everyone knew there was an emergency.  In February 2010, 40 islanders formed a protest march opposing the proposal to retire the sirens.  The campaigners accused the government of not listening to them, as an online petition calling for the sirens to be saved was signed by more than 2,000 people.  In April 2010, it was decided to dismantle the public warning system.  Emergency planners had proposed to use a new warning system that would contact residents by telephone however, this was abandoned due to technical limitations and local media and other communication methods are used instead. 
Following severe flooding in Upper Calder Valley in June 2000, the Environment Agency replaced its network of sirens, with eight being placed around Walsden, Todmorden, Hebden Bridge and Mytholmroyd. The network was designed to complement the agency's Floodline service. 
In November 2010, 36 flood warning sirens in Essex, including nine on Canvey, were retired following concerns from the county council that the system was "no longer fit for purpose".  The sirens were due to become obsolete in 2014. 
In September 2012, new flood warning sirens were installed in the Dunhills Estate in Leeds, as part of flood defence work at Wyke Beck.  In January 2014, flood sirens sounded for the first time in 30 years on the Isle of Portland. 
Broadmoor Hospital uses 13 sirens installed in 1952, which are tested weekly.  In July 2014, plans were put forward to retire 7 of the 13 alarms, which had last been properly activated in 1993.  The alarms are located in areas such as Sandhurst, Wokingham, Bracknell, Camberley and Bagshot.  In June 2016, the West London Mental Health Trust, who manages the hospital, proposed decommissioning the sirens altogether and replacing them with social media alerts through websites such as Twitter. 
There are several sirens in use around Avonmouth near Bristol to warn of chemical incidents from industry in the area. These are known as the Severnside Sirens.
North America Edit
In Canada, a nationwide network of Canadian Line Manufacturing sirens was established in the 1950s to warn urban populations of a possible Soviet nuclear attack. This system was tested nationwide twice in 1961, under the codenames Exercise Tocsin and "Tocsin B". The system was maintained until the 1970s, when advancements in military technology reduced the Soviet nuclear missile strike time from 3–5 hours to less than 15 minutes. Sirens can still be found in many Canadian cities, all in various states of repair. In Toronto, for instance, the network has been abandoned to the point where no level of government will take responsibility for its ownership.  A handful of sirens still remain in Toronto in older established neighbourhoods:
Sirens have recently been built within 3 kilometers of the Darlington and Pickering nuclear power plants in the province of Ontario. (Both plants are within 30 kilometers of each other.) These sirens will sound in the event of a nuclear emergency that could result in a release of radioactivity. Sirens have also been placed (and are tested weekly) in Sarnia, Ontario due to the large number of chemical plants in the vicinity.   These consist mainly of ATI HPSS32 sirens, as well as a Federal Signal Modulator in the rail yards and 3 Thunderbolt 1003s located at the Suncor plant.   Sirens have also been installed in and around the Grey Bruce Nuclear Generating Station. The sirens are on the plant and in the surrounding communities such as Tiverton, Ontario. One notable siren is a Federal Signal Modulator at the Bruce Nuclear Visitor's Centre. The Public Siren network as it is called, consists of mostly Whelens, Modulators, and Model 2s. One of the sirens in this network (a Model 2) is at Tiverton, which is about 10 km from the plant.
Many warning sirens in Ontario, Manitoba, Saskatchewan and Alberta are now used as tornado warning instruments. Smithers, British Columbia uses an old air raid siren as a noon-day whistle. One of the warning sirens was even used as a goal horn for the Quebec Nordiques between the mid 1980s and 1991. Caledonia, Ontario routinely uses an air raid siren to call in their local volunteer firefighters to the fire hall. NOAA Weather Radios in Canada are often used for advanced warnings about future severe storms whenever people are at home, at a business or in a car.
United States Edit
In the United States, several sets of warning tones have been used that have varied due to age, government structure, and manufacturer. The initial alerts used during World War II were the alert signal (a 3–5-minute steady, continuous siren tone) and the attack signal (a 3–5-minute warbling tone, or series of short tone bursts on devices incapable of warbling, such as whistles). The Victory Siren manual stated that when a manual generation of the warbling tone was required, it could be achieved by holding the "Signal" switch on for 8 seconds and off for 4 seconds. In 1950, the Federal Civil Defense Administration revised the signals, naming the alert signal "red alert" and adding an "all clear" signal, characterized by three 1-minute steady blasts with 2 minutes of silence between the blasts. 
Beginning in 1952, the Bell and Lights Air Raid Warning System,  developed by AT&T, was made available to provide automated transmission of an expanded set of alert signals:
- Red alert: Attack (Imminent)
- Yellow alert: Attack (Likely)
- White alert: All Clear
- Blue alert: Hi-Low
The "yellow alert" and "red alert" signals correspond to the earlier "alert" signal and "attack" signal, respectively, and the early Federal Signal AR timer siren control units featured the "take cover" button labeled with a red background and the "alert" button labeled with a yellow background. Later AF timers changed the color-coding, coloring the "alert" button blue, the "take cover" button yellow, and the "fire" button red (used to call out volunteer firefighters), thus confusing the color-coding of the alerts. In 1955, the Federal Civil Defense Administration again revised the warning signals, altering them to deal with concern over nuclear fallout. The new set of signals were the "alert" signal (unchanged) and the "take cover" signal (previously the "attack" signal). The "all clear" signal was removed because leaving a shelter while fallout was present would prove hazardous. 
Sirens began to replace bells for municipal warning in the early 1900s, but became commonplace following America's entry into World War II. Most siren models of this time were single-tone models which often sounded almost an octave higher in pitch than their European counterparts. Dual-tone sirens became more common in the 1950s, but had been used in some areas since about 1915. During the Cold War, standard signals were used throughout the country for civil defense purposes, referred to as "alert" and "attack." Volunteer fire departments generally used a different siren signal. Many towns, especially in California and New England, used coded air horns or diaphones for fire calls and reserved sirens for civil defense use.
Today, signals are determined by state and local authorities, and can vary from one region to another. The most common tones produced by sirens in the United States are "alert" (steady) and "attack" (wail). Other tones include Westminster Chimes (commonly used for the testing of electronic sirens), hi-lo, whoop, pulse, air horn, and fast wail.
The U.S. federal standard regarding emergency warning signals is defined in FEMA's Outdoor Warning Systems Guide, CPG 1-17,  published on March 1, 1980, which describes the Civil Defense Warning System (CDWS) and its warning signals. The language was slightly revised by FEMA's National Warning System Operations Manual, Manual 1550.2  published 03-30-2001:
- Attack warning: a 3 to 5-minute wavering tone on sirens or a series of short blasts on horns or other devices. The "attack warning" signal means an actual attack or accidental missile launch was detected, and people should take protective action immediately. The signal will be repeated as often as deemed necessary by local government authorities to get the required response from the population, including taking protective action from the arrival of fallout. This signal will have no other meaning and will be used for no other purpose. (However, sometimes the "attack" signals used for tornado warnings.)
- Attention or alert warning: a 3 to 5-minute steady signal from sirens, horns, or other devices. Local government officials may authorize use of this signal to alert the public of peacetime emergencies, normally tornadoes, flash floods, and tsunamis. With the exception of any other meaning or requirement for action as determined by local governments, the "attention" or "alert" signal will indicate that all persons in the United States should "turn on [their] radio or television and listen for essential emergency information".
- A third distinctive signal may be used for other purposes, such as a local fire signal.
- All clear: no all clear signal is defined by either document.
The most common tone, "alert", is widely used by municipalities to warn citizens of impending severe weather, particularly tornadoes which have earmarked the sirens as "Tornado Sirens". This practice is nearly universal in the Midwest and parts of the Deep South, where intense and fast-moving thunderstorms that can produce tornadoes occur frequently. The "alert" sound is a steady, continuous note. In seaside towns, "alert" may also be used to warn of a tsunami. Sirens that rotate will have a rising-and-falling tone as the direction of the horn changes. The "attack" tone is the rising and falling sound of an air raid or nuclear attack, frequently heard in war movies. It was once reserved for imminent enemy attack, but is today sometimes used to warn of severe weather, tsunamis, or even fire calls, depending on local ordinance.
There is no standard "fire" signal in the United States, and while the use of sirens by volunteer fire departments is still common, it is diminishing. In the dry areas of the American West, residents may be required to shut off outdoor water systems to ensure adequate pressure at fire hydrants upon hearing the signal. The "fire" signal can vary from one community to another. Three long blasts on a siren is one common signal, similar to the signal used by volunteer brigades in Germany and other countries, while other locales use the hi-lo signal described above. Some communities, particularly in New England and northern California, make use of coded blasts over a diaphone or air horn for fire signals, reserving the use of sirens for more serious situations. Still others use the "attack" tone as their fire call. Some communities make use of an "all clear" signal, or sound separate signals for fire calls and ambulance runs. Some fire signals in the U.S. are often blasted at least once a day, mostly at noon, to test the system, and are often referred to as "noon sirens" or "noon whistles". [ citation needed ]
CPG 1-17 recommends that a monthly test be conducted, consisting of the steady "attention" signal for no more than one minute, one minute of silence, and the "attack" signal for no more than one minute. A "growl test" signal is also described by CPG 1-17, when a siren must be tested more than once a month. This is typically a 1-second burst of sound to verify the proper operation of the siren without causing a significant number of people to interpret the test as an actual alert. Many cities in the U.S. periodically sound their sirens as a test, either weekly, monthly, or yearly, at a day and hour set by each individual city. [ citation needed ]
In the United States, there is no national level alert system. Normally, sirens are controlled on a county or local level, but some are controlled on a state level, such as in Hawaii. Sirens are usually used to warn of impending natural disaster while they are also used to warn of threats of military attacks, these rarely occur in the United States. Throughout the Great Plains, Midwest, and South, they are typically used to warn the public to take cover when a tornado warning is issued, sometimes even for severe thunderstorm warnings, and very rarely used for anything else. They are generally required in areas within a ten-mile radius of nuclear power plants. In the South and on the East Coast (except for Texas, Maine, Florida and New Hampshire), sirens are used to inform people about approaching hurricanes.
In Pierce County, Washington there is a system of sirens set up along the Puyallup and Carbon River valleys to warn residents of volcanic eruptions and lahars (giant mudslides) from Mt. Rainier.
Coastal communities, especially those in northern California, Oregon, Washington, Alaska, and Hawaii, use siren systems to warn of incoming tsunamis. In 2011, the city of Honolulu created an "Adopt-A-Siren" website for its tsunami sirens. The site is modeled after Code for America's "Adopt-a-Hydrant", which helps volunteers in Boston sign up to shovel out fire hydrants after storms. 
Some U.S. volunteer fire departments, particularly in rural areas, use sirens to call volunteers to assemble at the firehouse. This method is being used less frequently as technology advances. Some areas utilize their sirens as a last resort, relying more on cellular and paging technology however, a decreasing number of rural brigades are still outside the range of wireless communications and rely on sirens to activate the local volunteer brigade.
Many college campuses in the U.S., especially in the wake of the Virginia Tech shooting, have begun installing sirens to warn students in the event of dangerous incidents. [ citation needed ] Sirens in the United States have been replaced by NOAA Weather Radios for advanced warnings about future severe storms whenever people are inside cars or buildings.
A series of 98 electronic sirens, making up a large-scale public-address system (the "Sydney CBD Emergency Warning System") and including 13 variable-message signs, are installed in the Sydney central business district. While installed in the months preceding the 2007 APEC conference, they are designed to be a permanent fixture and are tested on a monthly basis. 
Smaller-scale sirens are also deployed, like the Model 5 or Model A, which are used at fire stations for call-outs and at Sydney's beaches for shark alarms. Alarms are also used around prisons for breakouts and at many factories and schools to announce start and finish times.
A siren is located at the Kwinana BP plant south of Perth, which is tested every Monday. It is used to evacuate the plant in case of an emergency and can be heard in Kwinana and certain parts of Rockingham. It can also be used to warn of severe weather and potentially dangerous emergencies on the Kwinana Industrial Strip.
In South Australia, a number of Country Fire Service stations have a mechanical siren on or near the station. These are only activated when the brigade are responding to bushfire or grassfire events and for testing. They are not activated for every call, only as a public alert for the presence of bushfires.
In Victoria, many Country Fire Authority stations have a siren installed that is used to summon volunteers to an emergency callout, as well as consequently alerting the local community of brigade activity. Due to a variety of siren types in use across the state, there are 2 signals that are used, differentiated by length: 
- Emergency callout: siren sounds for no longer than 90 seconds.
- Community alert: siren sounds for no shorter than 5 minutes.
In Melbourne's CBD, there is a set of sirens installed to warn of attack and extreme flooding. These became necessary after the Bourke and Flinders St. attacks, where people were killed as a result of a vehicle purposefully driving into pedestrians.
In Queensland, Whelen Vortex 4 sirens have been installed as part of the Somerset Regional Council Flood Warning System. At nearby Grantham, a Whelen WPS2906 which features both warning tones and pre-recorded messages provides early warning in the event of flooding.
New Zealand Edit
Lower Hutt,  Napier,  Wanganui,  and the former Waitakere City area of Auckland  each have a network of civil defense sirens. The networks in Lower Hutt and Napier are bolstered by fire sirens that also function as civil defense sirens. Lower Hutt's network is further bolstered by selected industrial sirens that double as civil defence sirens. In the western Bay of Plenty, several fire sirens also serve as civil defense sirens, and there are dedicated civil defense sirens at the Bay Park Raceway in Mount Maunganui, Tokoroa, and Whangamata (which has two). Additionally, Tokoroa, Putaruru, Tirau, and Whangamata have fire sirens serving double duty as civil defense sirens.  In the years following the tsunamis of the Indian Ocean earthquake in 2004, Meerkat electronic sirens were installed in all populated areas of the west coast lower than 10 metres.
Warning sounds vary from area to area, including rising and falling notes and Morse code sirens. Communities with volunteer fire brigades use a continuous note on all sirens for civil defense, and a warbling siren on the fire station siren only for fire callouts. Civil defense uses a distinctive "sting" siren that is used by all radio stations nationwide, but is currently only used for civil defense sirens in Wanganui.
This Day In History: The First Air Raids On Britain Takes Place (1915)
On this date in 1915, the first recorded air-raid on Britain took place. The raid was carried out by German Zeppelin airships. The Zeppelin was a massive airship that could fly at great heights. These ships were massive dirigibles that were guided by a crew who used an engine to guide the ship. The airships were designed by the German inventor Ferdinand Graf von Zeppelin in 1900. He adapted what was a French invention and developed a ship that could fly higher and offered better control to the crew. The Zeppelin was undoubtedly the best dirigible of the era. Before the war, the Germans believed that these airships could be useful and adapted for military uses. They recognized that they could be employed for reconnaissance. The Zeppelins were also adapted by the Germans so that they could drop bombs on targets. Bombs were attached to the Zeppelin and they were dropped by the crew when they were over a target. The bombs were released when the airship was directly overhead an objective. The bomb loads that these ships could take were limited even though the Zeppelins were the largest airships that had even been built to that data.
Zeppelin the designer of the German airships.
The Zeppelins were massive but this also made them more vulnerable. The heavy steel framed dirigibles were not robust and they were liable to explode. The airships were dependent on highly flammable hydrogen gas rather than helium. This was because hydrogen was needed to lift the huge airship.
In January 1915, three types of Zeppelins were used in the first air raid on England. Germany employed three zeppelins, the L.3, the L.4, and the L.6, in the mission. The L6 was forced to turn back because of mechanical problems. The two remaining Zeppelins took almost a day to reach the coast of England. They came overhead the town of Yarmouth on the coast of East Anglia. The airships dropped several bombs on the town. Yarmouth was not prepared for the attack and it shocked the inhabitants. Some men on their way to work in the early hours of the morning spotted strange lights, little did they realize that they were the lights of giant airships about to attack the sleeping town. The Zeppelins bombed hit the town and caused considerable damage to some houses. Two people were killed in the raids and several more are wounded. The airships then floated along the coast to the nearby town of Kings-Lynne here another two people were killed. After they had dropped all their bombs the two airships returned to Germany, safely.
The air raid caused considerable shock in England and many people feared that future air raids would bring even more death and destruction.
Mr. Tornado is the remarkable story of the man whose groundbreaking work in research and applied science saved thousands of lives and helped Americans prepare for and respond to dangerous weather phenomena.
The Polio Crusade
The story of the polio crusade pays tribute to a time when Americans banded together to conquer a terrible disease. The medical breakthrough saved countless lives and had a pervasive impact on American philanthropy that continues to be felt today.
Explore the life and times of L. Frank Baum, creator of the beloved The Wonderful Wizard of Oz.
The first air bomb: Venice, 15 July 1849
On 22 August 1849, the Republic of San Marco surrendered to Austria. The Republic was formed after a revolt in Venice against Austrian rule in March 1848. The Austrians eventually besieged Venice, leading to starvation and outbreaks of cholera in the city. During this siege, they launched the first air raids in history, by unmanned balloons which floated over Venice carrying bombs. The British press didn't take any notice of this at the time, but the following account appeared in the Morning Chronicle a week after the surrender:
The Soldaten Freund publishes a letter from the artillery officer Uchatius, who first proposed to subdue Venice by ballooning. From this it appears that the operations were suspended for want of a proper vessel exclusively adapted for this mode of warfare, as it became evident, after a few experiments had been made, that, as the wind blows nine times out of ten from the sea, the balloon inflation must be conducted on board ship and this was the case on July the 15th, the occasion alluded to in a former letter, when two balloons armed with shrapnels ascended from the deck of the Volcano war steamer, and attained a distance of 3,500 fathoms in the direction of Venice and exactly at the moment calculated upon, i. e., at the expiration of twenty-three minutes, the explosion took place. The captain of the English brig Frolic, and other persons then at Venice, testify to the extreme terror and the morale effect produced on the inhabitants.
A stop was put to further exhibitions of this kind by the necessity of the Vulcan going into docks to undergo repairs, which the writer regrets the more, as the currents of wind were for a long time favourable to his schemes. One thing is established beyond all doubt (he adds), viz., that bombs and other projectiles can be thrown from balloons at a distance of 5,000 fathoms, always provided the wind be favourable. 1
Some comments. It's hard to find reliable information on these attacks. The best account I've seen is by Lee Kennett and he's not sure how many balloons were released, saying that the largest number he has seen is two hundred. 2 This doesn't fit well with the Morning Chronicle article, which seems to suggest that only two balloon bombs were ever launched. This is supposedly based on a letter written by the inventor of the balloon bombs, Franz von Uchatius, so if it's accurate should be preferred over secondary sources. 3
But whether the number was two or two hundred, it doesn't seem like the balloon bombs had much effect on the course of the siege, which went on for another five weeks -- despite the reference made in the Morning Chronicle to 'the extreme terror and the morale effect produced on the inhabitants'. That was clearly what was intended, as the bombs were released (or maybe detonated) by a timer, and couldn't possibly hit specified targets from a balloon drifting above the city. 4 More importantly, the bombs used were filled with shrapnel, which isn't much use for anything but killing and maiming people. So there were few qualms on the part of the Austrians about targeting and killing civilians. Which they went on to do with presumably much greater efficiency when they later bombarded the city with more conventional artillery, averaging a thousand shells a day. 5
Finally, the air raids of 1849 seem to have had as little impact on the wider world (at least the English-speaking part of it) as they did on Venice. As noted above, there was very little notice taken in the British press, and I've come across only one meager reference to Venice in books published before 1914 (and that in a book translated from the German, written by the German military balloonist Hermann Moedebeck). So it doesn't seem like they inspired anyone to find a better way to bomb cities from the air that was an idea which had to be invented all over again. Which it was, of course, and Venice's next air raid was on 24 May 1915.