Benito Mussolini's Fascists march on Rome; King Victor Emmanuel III appoints Mussolini prime minister, beginning Fascist rule in Italy.
Under the Anglo-Irish Treaty, the Irish Free State is established as a self-governing dominion of the British Commonwealth.
The Treaty on the Creation of the USSR unites Russia, Ukraine, Belarus and the Transcaucasian Federation into the Union of Soviet Socialist Republics.
Vladimir Lenin, founder of the Soviet state, dies after a series of strokes, opening a power struggle won by Stalin.
The peace treaty ending the war between Germany and the Allies is signed in the Hall of Mirrors, imposing war guilt, territorial losses and heavy reparations on Germany.
Former Tsar Nicholas II, his wife, their children and their retainers are shot by the Bolsheviks in Yekaterinburg.
John Logie Baird demonstrates a mechanical television system transmitting live moving images in London.