April 20 in history:
1303 The University of Rome La Sapienza was instituted by Pope Boniface VIII.
1494 Johannes Agricola, German Protestant reformer was born (d. 1566) .
1534 Jacques Cartier began the voyage during which he discovered Canada and Labrador.
1657 Admiral Robert Blake destroyed a Spanish silver fleet under heavy fire at Santa Cruz de Tenerife.
1657 Freedom of religion was granted to the Jews of New Amsterdam (later New York City).
1689 The former King James II of England, then deposed, lay siege to Derry.
1775 American Revolutionary War: the Siege of Boston began.
1792 France declared war on Austria, beginning of French Revolutionary Wars.
1809 Two Austrian army corps in Bavaria are defeated by a First French Empire army led by Napoleon I of France at the Battle of Abensberg on the second day of a four day campaign which ended in a French victory.
1810 The Governor of Caracas declared independence from Spain.
1828 René Caillié becomes the first non-Muslim to enter Timbouctou.
1861 American Civil War: Robert E. Lee resigned his commission in the United States Army in order to command the forces of the state of Virginia.
1871 The Civil Rights Act of 1871 became law.
1889 Adolf Hitler, German Nazi dictator, was born (d. 1945) .
1893 Joan Miró, Spanish painter, was born (d. 1983).
1914 Forty-five men, women, and children died in the Ludlow Massacre during a Colorado coal-miner’s strike.
1918 Manfred von Richthofen, aka The Red Baron, shot down his 79th and 80th victims marking his final victories before his death the following day.
1941 Ryan O’Neal, American actor, was born.
1945 World War II: US troops captured Leipzig, Germany.
1945 World War II: Fuehrerbunker: Adolf Hitler made his last trip to the surface to award Iron Crosses to boy soldiers of the Hitler Youth.
1948 Craig Frost, American musician (Grand Funk & Bob Seger), was born.
1949 Jessica Lange, American actress, was born.
1953 Sebastian Faulks, British novelist, was born.
1958 The first temple of The Church of Jesus Christ of Latter-day Saints in the Southern Hemisphere opened in Hamilton.
1961 Failure of the Bay of Pigs Invasion of US-backed troops against Cuba.
1964 BBC Two launched with the power cut because of the fire at Battersea Power Station.
1972 Apollo 16 landed on the moon commanded by John Young.
1978 Korean Air Flight 902 was shot down by Soviets.
1980 Climax of Berber Spring in Algeria as hundreds of Berber political activists were arrested.
1985 ATF raid on The Covenant, The Sword, and the Arm of the Lord compound in northern Arkansas.
1986 Pianist Vladimir Horowitz performed in his native Russia for the first time in 61 years.
1986 Cameron Duncan, New Zealand director, was born.
1986 Professional basketball player Michael Jordan set a record for points in an NBA playoff game with 63 against the Boston Celtics.
1998 German terrorist group Red Army Faction announcesd their dissolution after 28 years.
2007 Johnson Space Center Shooting: A man with a handgun barricaded himself in NASA’s Johnson Space Center in Houston before killing a male hostage and himself.
2010 – Deepwater Horizon drilling rig explosion killed 11 and causes rig to sink, initiating a massive oil discharge in the Gulf of Mexico.
Sourced from Nz History Online and Wikipedia