Chad: African Liberation Day Mali: African Liberation Day Argentina: Anniversary of the First Independent Government in Buenos Aires
1085 - Alfonso VI of Castile takes Toledo, Spain back from the Moors.
1420 - Henry the Navigator is appointed governor of the Order of Christ.
1521 - The Diet of Worms ends when Charles V, Holy Roman Emperor, issues the Edict of Worms, declaring Martin Luther an outlaw.
1659 - Richard Cromwell resigns as Lord Protector of England following the restoration of the Long Parliament, beginning a second brief period of the republican government called the Commonwealth of England.
1738 - A treaty between Pennsylvania and Maryland ends the Conojocular War with settlement of a boundary dispute and exchange of prisoners.
1787 - In Philadelphia, Pennsylvania, delegates convene a Constitutional Convention to write a new Constitution for the United States. George Washington presides.
1809 - A group of patriots in Charcas (Today's Sucre) revolt agaist Joseph Bonaparte's reign, starting the South American Independence War
1810 - In the May Revolution, citizens of Buenos Aires expel the Viceroy during the Semana de Mayo.
1837 - The Patriots of Lower Canada (Quebec) rebel against the British for freedom.
1865 - In Mobile, Alabama, 300 are killed when an ordnance depot explodes.
1878 - Gilbert and Sullivan's H.M.S. Pinafore opens at the Opera Comique in London.
1895 - Playwright, poet, and novelist Oscar Wilde is convicted of "committing acts of gross indecency with other male persons" and sentenced to serve two years in prison.
1895 - The Republic of Formosa is formed, with Tang Ching-sung as the president.
1914 - The United Kingdom's House of Commons passes the Home Rule Act for devolution in Ireland.
1925 - Scopes Trial: John T. Scopes is indicted for teaching Charles Darwin's theory of evolution.
1926 - Sholom Schwartzbard assassinates Symon Petliura, the head of the Paris-based government-in-exile of Ukrainian People's Republic.
1935 - Jesse Owens of Ohio State University breaks five world records and ties a sixth at the Big Ten Conference Track and Field Championships in Ann Arbor, Michigan.
1936 - The Remington Rand strike, led by the American Federation of Labor, begins.
1938 - Spanish Civil War: The bombing of Alicante takes place, with 313 deaths.
1940 - World War II: The Battle of Dunkirk begins.
1946 - The parliament of Transjordan makes Abdullah I of Jordan their king.
1953 - Nuclear testing: At the Nevada Test Site, the United States conducts its first and only nuclear artillery test.
1953 - The first public television station in the United States officially begins broadcasting as KUHT from the campus of the University of Houston.
1955 - In the United States, a night time F5 tornado strikes the small city of Udall, Kansas, killing 80 and injuring 273. It is the deadliest tornado to ever occur in the state and the 23rd deadliest in the U.S.
1955 - First ascent of Kangchenjunga (8,586 m.), the third highest mountain in the world, by a British expedition.
1961 - Apollo program: U.S. President John F. Kennedy announces before a special joint session of Congress his goal to initiate a project to put a "man on the moon" before the end of the decade.
1963 - In Addis Ababa, Ethiopia, the Organisation of African Unity is established.
1966 - Explorer program: Explorer 32 launches.
1966 - The first prominent DaZiBao during the Cultural Revolution in China is posted at Peking University.
1967 - Celtic F.C. becomes the first United Kingdom team to reach a European Cup final and also the first to win it, beating Inter Milan 2-1.
1977 - Star Wars is released. It rapidly becomes a cult classic and is the start of a six-movie franchise.
1979 - American Airlines Flight 191: In Chicago, a McDonnell Douglas DC-10 crashes during takeoff at O'Hare International Airport killing 271 on board and two people on the ground.
1981 - In Riyadh, the Gulf Cooperation Council is created between Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates.
1982 - HMS Coventry is sunk during the Falklands War.
1985 - Bangladesh is hit by a tropical cyclone and storm surge, which kills approximately 10,000 people.
1997 - A military coup in Sierra Leone replaces President Ahmad Tejan Kabbah with Major Johnny Paul Koromah.
1999 - The United States House of Representatives releases the Cox Report which details the People's Republic of China's nuclear espionage against the U.S. over the prior two decades.
2000 - Liberation Day of Lebanon. Israel withdraws its army from most of the Lebanese territory after 22 years of its first invasion in 1978.
2001 - 32-year-old Erik Weihenmayer, of Boulder, Colorado, becomes the first blind person to reach the summit of Mount Everest.
2002 - China Airlines Flight 611: A Boeing 747-200 breaks apart in mid-air and plunges into the Taiwan Strait killing 225 people.
2002 - A train crash in Tenga, Mozambique kills 197 people.
2008 - An EF5 tornado ravages through Parkersburg, Iowa, only the seventh in the state since 1918, killing 5 and causing hundreds of thousands of dollars in physical damage.
2009 - North Korea allegedly tests its second nuclear device. Following the nuclear test, Pyongyang also conducted several missile tests bulding tensions in the international community.