Lots of shit happened on 4/20
* 1884 - Pope Leo XIII publishes the encyclical, Humanum Genus.
* 1902 - Pierre and Marie Curie refine radium chloride.
* 1908 - Opening day of competition of the New South Wales Rugby League.
* 1912 - Opening day for baseball stadiums Tiger Stadium in Detroit, Michigan, and Fenway Park in Boston, Massachusetts.
* 1914 - Seventeen men, women, and children die in the Ludlow Massacre during a bitter Colorado coal-miner's strike.
* 1918 - Manfred von Richthofen, aka The Red Baron, shoots down his 79th and 80th victims marking his final victories before his death the following day.
* 1926 - Western Electric and Warner Bros. announce Vitaphone, a process to add sound to film.
* 1928 - René Caillié is first non-Muslim to enter in Timbouctou.
* 1945 - World War II: US troops capture Leipzig, Germany, only to later cede the city to the Soviet Union.
* 1945 - World War II: U.S. B-29 bombers destroy the Musashi Aircraft plants, halting production of the Nakajima Ki-84 fighter planes.
* 1960 - Inauguration of Brasilia.
* 1961 - Failure of the Bay of Pigs Invasion of US troops against Cuba.
* 1964 - BBC Two launches with the power cut because of the fire at Battersea Power Station.
* 1967 - A Swiss Britannia turboprop crashes at Toronto, Canada, killing 126.
* 1968 - A South African Airways Boeing 707 crashes during takeoff at Windhoek, South-West Africa, killing 122.
* 1968 - English politician Enoch Powell makes his controversial Rivers of Blood speech.
* 1972 - Apollo 16 lands on the Moon.
* 1978 - Korean Air Flight 902 shot down by Soviets.
* 1979 - Jimmy Carter's rabbit incident.
* 1980 - Climax of Berber Spring in Algeria as hundreds of Berber political activists are 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. The concert was viewed by millions on television.
* 1986 - Professional basketball player Michael Jordan sets all-time record for points in a NBA playoff game with 63 against the Boston Celtics.
* 1998 - TAME Boeing 727-200 chartered by Air France crashes into Cerro El Cable mountain after takeoff from Bogotá, Colombia, killing 53.
* 1998 - German terrorist group Red Army Faction announces their dissolution after 28 years.
* 1999 - Eric Harris and Dylan Klebold kill 12 students and a teacher before killing themselves in the Columbine High School massacre.
* 1999 - Largest bombing of Kosovo by the United States in the Kosovo War.
* 2004 - In Iraq, 12 mortars are fired on Abu Ghraib Prison by insurgents, killing 22 detainees and wounding 92.
* 2004 - In Utica, IL 9 people were killed when an F3 tornado hits downtown. The tornado was one of 30 spanning from northern Illinois to northern Indiana.
