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August
20

August 20 has seen revolutionary leaders assassinated, Viking expeditions launched, and liberation movements triumph.

On This Day in History

1940
Politics

Trotsky Assassinated

Soviet exile Leon Trotsky was fatally wounded with an ice axe by Ramón Mercader, an agent of Stalin, in Mexico City. The assassination eliminated Stalin's last major political rival.

1968
War & Conflict

Soviet Invasion of Czechoslovakia

Soviet-led Warsaw Pact forces invaded Czechoslovakia, crushing the Prague Spring reform movement. The invasion ended Alexander Dubček's experiment with 'socialism with a human face.'

1882
Entertainment

Tchaikovsky's 1812 Overture Premieres

Tchaikovsky's famous 1812 Overture premiered in Moscow, complete with real cannon fire. The piece, composed to commemorate Russia's victory over Napoleon, became one of the most popular orchestral works.

917
War & Conflict

Battle of Achelous

Tsar Simeon I of Bulgaria defeated the Byzantine Empire in one of the bloodiest medieval battles. The victory established Bulgaria as a major power in southeastern Europe.

1858
Science

Darwin and Wallace Present Evolution Theory

Charles Darwin and Alfred Russel Wallace jointly presented their theory of evolution by natural selection to the Linnean Society of London. The presentation launched a scientific revolution.

1977
Science

Voyager 2 Launched

NASA launched the Voyager 2 spacecraft on its grand tour of the outer planets. It became the only spacecraft to visit all four giant planets—Jupiter, Saturn, Uranus, and Neptune—and continues transmitting data from interstellar space.

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