Nazi Germany and its collaborators systematically murder some six million European Jews, along with millions of other victims.
At Pác Bó, Hồ Chí Minh presides over the founding of the League for the Independence of Vietnam (Việt Minh).
Nazi Germany and its allies launch a massive invasion of the Soviet Union, opening the Eastern Front, the largest theatre of the Second World War.
German and Finnish forces besiege Leningrad for nearly 900 days; around a million civilians die, mostly from starvation.
The Imperial Japanese Navy launches a surprise attack on the US naval base at Pearl Harbor, Hawaii, bringing the United States into World War II.
After the 1857 rebellion, the Government of India Act transfers rule from the East India Company to the British Crown; the Mughal Empire formally ends.
Germany invades Poland, starting the deadliest conflict in human history, which ends with Japan's formal surrender on 2 September 1945.