July 21st

2011
STS-135 lands. This space shuttle was the 135th and the last space shuttle flight of American Space Shuttle program.
STS-135
2010
President Barack Obama signed into law the most sweeping overhaul of U.S. lending and high finance rules since the 1930s.
Dodd–Frank Wall Street Reform and Consumer Protection Act ...
2008
Former Bosnian Serb leader Radovan Karadzic, one of the world's top war crimes fugitives, was arrested in a Belgrade suburb by Serbian security forces.
Radovan Karadžić
2007
'Harry Potter and the Deathly Hallows', the final volume in the book series by J.K. Rowling, went on sale.
Harry Potter and the Deathly Hallows
2002
Telecommunications giant WorldCom Inc. filed for bankruptcy protection after disclosing it had inflated profits by nearly $4 billion through deceptive accounting.
MCI Inc.
1998
Astronaut Alan Shepard died at age 74.
Alan Shepard
1988
Massachusetts Gov. Michael Dukakis accepted the Democratic presidential nomination at the party's convention in Atlanta.
Michael Dukakis
1983
Lowest temperature ever measured on Earth. Vostok Station, a Russian station on Antarctica experienced the lowest temperatures ever measured in recorded human history. The temperatures fell to −128.6 °F (−89.2 °C)
Lowest temperature recorded on Earth
1980
Mary Eugenia Charles is elected as PM of Dominica. Her election to office made her the first female and the longest PM of the Commonwealth of Dominica. She is also the first elected female head of state in the Americas.
Eugenia Charles
1977
Libyan–Egyptian War begins. This short war between Libya and Egypt started with Libya striking Egyptian cities. The war lasted for 2 days with a ceasefire on July 24.
Libyan–Egyptian War
1970
Aswan Dam opens in Egypt, enables human control of the flooding of the Nile.
Nile
1969
First person walks on the Moon. Neil Armstrong became the first person to walk on the Moon. He stepped on the Moon's surface almost 7 hours after Apollo 11, the space craft that carried them, landed on the Sea of Traquility on the Moon. After stepping on the Moon, Armstrong uttered his famous words, "one small step for [a] man, one giant leap for mankind."
Apollo 11
1961
Capt. Virgil "Gus" Grissom became the second American to rocket into a sub-orbital pattern around the Earth, flying on the Liberty Bell 7.
Mercury-Redstone 4
1954
France surrendered North Vietnam to the Communists.
Battle of Dien Bien Phu
1949
The U.S. Senate ratified the North Atlantic Treaty.
North Atlantic Treaty
1944
The Democratic National Convention in Chicago nominated Sen. Harry S. Truman to be vice president.
1944 Democratic National Convention
1925
In the 'Monkey Trial,' John T. Scopes was found guilty of violating Tennessee state law by teaching evolution.
Scopes Trial
1904
After 13 years, the 4,607-mile Trans-Siberian railway is completed.
1899
Author Ernest Hemingway was born in Oak Park, Ill.
Ernest Hemingway
1873
The first train robbery west of the Mississippi was pulled off by Jesse James and his gang.
James–Younger Gang
1861
The first Battle of Bull Run was fought at Manassas, Va., during the Civil War, resulting in a Confederate victory.
First Battle of Bull Run
1831
Belgium became independent as Leopold I was proclaimed King of the Belgians.
Belgian Revolution
365
Crete Earthquake followed by tsunami around the Eastern Mediterranean allegedly destroys Alexandria.
365 Crete earthquake