John Logie Baird demonstrates a mechanical television system transmitting live moving images in London.
Charles Lindbergh flies solo and nonstop from New York to Paris in the Spirit of St. Louis.
Vladimir Lenin, founder of the Soviet state, dies after a series of strokes, opening a power struggle won by Stalin.
Alexander Fleming notices Penicillium mould killing bacteria, paving the way for the antibiotic era.
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.