The Arcadia Conference (First Washington Conference) concludes, which set the initial military strategy of the United States of America and Great Britain. It also creates the United Nations (with 26 initial signatories to Declaration by United Nations).

The Wannsee Conference (Wannseekonferenz), called by the chief architect of the Holocaust, director of the Reich Main Security Office SS-Obergruppenführer Reinhard Heydrich (having been given written permission by Hermann Göring to prepare and submit 'a total solution of the Jewish question'), takes place in the Berlin suburb of Wannsee. Its purpose was to ensure cooperation of various government departments in the implementation of the Final Solution of the Jewish Question. Secondarily, the conference would decide on what made someone a Jew for the purpose of genocide. Heinrich Himmler's SS would then become entirely responsible for carrying out the extermination once the Jews were deported to occupied Poland.

On 27 May 1942 Operation Anthropoid is conducted by the British Special Operations Executive with the approval of the Czechoslovak government-in-exile. The attack succeeded: Reinhard Heydrich was fatally wounded and would die on 4 June; thus the chief architect of the Holocaust was assassinated. The Nazis would avenge the death by massacring the village Lidice: All men over 15 years of age in the village were executed on 10 June; 11 men who weren't in the village were later arrested and executed; women and children were to be deported to the extermination camp Kulmhof [Chełmno] except a few children considered racially fitting for Germanisation. Around 340 people in all were killed in reprisal (192 men, 60 women and 88 children).