Today:
1788: New Hampshire became the 9th state to ratify the U.S. Constitution, making the Constitution officially effective.
1791: King Louis XVI and the French royal family were arrested at Varennes while trying to flee revolutionary France.
1834: Cyrus McCormick received a patent for his mechanical reaper, an invention that helped transform agriculture.
1864: During the American Civil War, the Battle of Jerusalem Plank Road began near Petersburg, Virginia.
1898: The United States captured Guam from Spain during the Spanish-American War.
1942: German forces under Erwin Rommel captured Tobruk in North Africa during World War II.
1945: The Battle of Okinawa effectively ended, one of the bloodiest battles of World War II in the Pacific.
1964: Three civil rights workers, James Chaney, Andrew Goodman, and Michael Schwerner, disappeared in Mississippi; they were later found murdered.
1982: John Hinckley Jr. was found not guilty by reason of insanity for the attempted assassination of President Ronald Reagan.
2004: SpaceShipOne became the first privately funded human spaceflight to reach space.