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Today in History, August 20th

On August 20, 1968, Soviet-led armies invaded Czechoslovakia to end the Prague Spring. Plus the NFL's roots and Viking 1's launch.

By Today in History Updated November 10, 2026 3 min read Sources checked

Published August 20, 2026 · Last updated November 10, 2026

August 20 is best known for 1968, when Soviet-led Warsaw Pact armies invaded Czechoslovakia to crush the Prague Spring. The date also saw the founding meeting of the league that became the NFL in 1920 and the launch of NASA’s Viking 1 to Mars in 1975.

The big story: Tanks end the Prague Spring (1968)

For a few months in 1968, Czechoslovakia tried loosening the Communist grip from the inside. Alexander Dubček, the Communist Party leader, promised free speech, freedom of religion, an end to censorship, democratic elections and more self-rule for Slovakia. He called it “socialism with a human face.” Moscow was not charmed. Leonid Brezhnev warned Dubček to stop, and when he did not, the answer came on the night of August 20, 1968. Nearly 200,000 troops from the Soviet Union, East Germany, Poland, Hungary and Bulgaria poured across the border. Crowds took to the streets in protest, and over the following days more than 100 protesters were shot dead. Dubček and other leaders were taken to Moscow, and he came home having agreed to scale back the reforms. In April 1969 he was replaced by Gustáv Husák, and a long period of “normalization” followed. The reformers’ moment came again in 1989, when Václav Havel was elected president.

More events on August 20

Year	What happened
1619	The first recorded enslaved Africans reached the English colony of Jamestown, Virginia, in late August. The arrival is often dated to August 20.
1794	Gen. “Mad” Anthony Wayne defeated the Northwest Indian Confederation at the Battle of Fallen Timbers in the Northwest Territory.
1804	Sgt. Charles Floyd died, probably of a ruptured appendix. He was the only member of the Lewis and Clark expedition to die on the journey.
1862	Horace Greeley’s New York Tribune published “The Prayer of Twenty Millions,” pressing President Lincoln to act against slavery. Lincoln issued his preliminary Emancipation Proclamation about a month later.
1914	The German army captured Brussels in the opening weeks of World War I.
1920	Seven men, including Jim Thorpe, met at a car showroom in Canton, Ohio, and laid the groundwork for the American Professional Football Association, forerunner of the NFL.
1940	Exiled Soviet revolutionary Leon Trotsky was attacked at his home near Mexico City by a Stalinist agent. He died the next day.
1974	Newly sworn-in President Gerald Ford, who had taken over after Richard Nixon’s resignation, chose Nelson Rockefeller as his vice president.
1975	NASA launched Viking 1 from Cape Canaveral. Nearly a year later it landed on Mars at Chryse Planitia.
2017	Comedian and actor Jerry Lewis died at 91.

Born on August 20

1833: Benjamin Harrison, 23rd U.S. president and grandson of President William Henry Harrison, born in North Bend, Ohio.
1910: Eero Saarinen, architect of the Gateway Arch in St. Louis, born in Kirkkonummi, Finland.
1974: Amy Adams, film actress, born in Aviano, Italy, where her father was serving in the U.S. military.