12 May — World War II – Second Battle of Kharkov: In the eastern Ukraine, the Soviet Army initiates a major offensive. During the battle the Soviets capture the city of Kharkov from the German Army, only to be encircled and destroyed.
21 May — World War II: Mexico declares war against Germany after the sinking of the Mexican tanker Faja de Oro by the German U-boat, U-160, off Key West.
10 June — World War II: The Gestapo massacres 173 male residents of Lidice, Czechoslovakia also in reprisal for the killing of Heydrich in the village.
11 June — Plans are made for the deportation of Jews from France, Belgium and the Netherlands.
23 June — The experimental early type of a nuclear reactor led to Leipzig L-IV experiment accident, becoming the first nuclear accident in history and consisting of steam explosion and reactor fire in Leipzig.
2 July — Soviet, American and British newspapers report that more than 1,000,000 Jews have already been exterminated by the Nazi regime across occupied Europe.
4 July — World War II: Twenty-four ships are sunk by German bombers and submarines after Convoy PQ 17 to the Soviet Union is scattered in the Arctic Ocean to evade the German battleship Tirpitz.
14 July — World War II: Germany introduces the Ostvolk Medal for Soviet personnel in Wehrmacht, on the same day that the first Dutch Jews are deported to Auschwitz.
19 July — World War II – Battle of the Atlantic: German Grand Admiral Karl Dönitz orders the last U-boats to withdraw from their United States Atlantic coast positions, in response to an effective American convoy system.
22 July — Holocaust: The systematic deportation of Jews from the Warsaw Ghetto begins, with many being transported to the new extermination camp at Treblinka.
August - Deportation of Croatian Jews to Auschwitz begins.
22 August — Brazil breaks diplomatic relations and declares war on Germany and Italy.[3][4]
30 August — Luxembourg is formally annexed to the German Reich.
3 October — The first A-4 rocket is successfully launched from Test Stand VII at Peenemünde, Germany. The rocket flies 147 kilometers wide and reaches a height of 84.5 kilometers, becoming the first man-made object to reach space.
5 October - Himmler orders all Jews in concentration camps across Germany to be transferred to Auschwitz or Majdanek.
14 October — A German U-boat sinks the ferry SS Caribou, killing 137.
23 October—4 November – World War II – Second Battle of El Alamein: British troops go on the offensive against the Axis forces.
10 November — World War II: In violation of a 1940 armistice, Germany invades Vichy France, following French Admiral François Darlan's agreement to an armistice with the Allies in North Africa.
23 November — A German U-boat sinks the SS Benlomond off the coast of Brazil. One crewman, a Chinese second steward named Poon Lim, is separated from the others and spends 130 days adrift until he is rescued on 3 April 1943.
28 December -
- Hitler orders Greece and Crete to be fortified and Balkan rebellions to be suppressed firmly and approves the withdrawal of Army Group A from the Caucasus.
- Sterilization experiments begin on women at Birkenau.[6]
^Treblinka - ein Todeslager der "Aktion Reinhard", in: "Aktion Reinhard" - Die Vernichtung der Juden im Generalgouvernement, Bogdan Musial (ed.), Osnabrück 2004, pp. 257-81.