Cong during the Vietnam War. May 20 – WWII: The Battle of Crete begins, as Germany launches an airborne invasion of Crete, the first mainly airborne invasion in military history. May 21 – sinks the U.S.-flagged off the west African coast, having allowed the passengers and crew to disembark. May 24 – WWII: In the North Atlantic, sinks British battlecruiser , killing all but 3 crewmen, from a total of 1,418 aboard the pride of the Royal Navy. British submarine torpedoes and sinks Italian ocean liner . May 26 – WWII: In the North Atlantic, Fairey Swordfish aircraft from the carrier cripple the steering of in an aerial torpedo attack. May 27 WWII: Franklin D. Roosevelt, President of the United States, proclaims an "unlimited national emergency." WWII: German battleship Bismarck is sunk in the North Atlantic, killing 2,300. It is eventually found in 1989. The Swiss Socialist Federation is banned. May 29 – The Disney animators' strike begins, due to lack of recognition by Walt Disney of his animators' inequities of pay and privileges. May 30 – WWII: Manolis Glezos and Apostolos Santas tear down the Nazi swastika on the Acropolis in Athens and replace it with the Greek flag. May 31 – Anglo-Iraqi War: British troops complete the re-occupation of the Kingdom of Iraq, returning Prince 'Abd al-Ilah to power as regent for Faisal II. June June 1 – WWII: The Battle of Crete ends, as Crete surrenders to invading German forces. June 4 Guidelines for the Conduct of the Troops in Russia are issued by Nazi high-command through OKW. This order (a lesser known precursor to the Commisar Order) explicitly commands that Jews (in addition to Bolshevik partisans and Commisars) be killed. In a sense, this order – in combination with the Commissar Order about to be delivered, and Goring's instruction to Heydrich to look into logistics later in the month, that is mentioned at the beginning of the Wannsee Conference of the following year – inaugurates the European Holocaust of the Jews. June 5 Second Sino-Japanese War: Four thousand Chongqing residents are asphyxiated in a bomb shelter during the Bombing of Chongqing. Smederevo Fortress explosion: A Serbian ammunition depot explodes at Smederevo on the outskirts of Belgrade, Serbia, killing 2,500 and injuring over 4,500. June 6 – WWII: The Commissar Order is issued by Oberkommando der Wehrmacht, requiring all Soviet political commissars identified in Operation Barbarossa among