Wikipedia:Selected anniversaries/April 20

This is a list of selected April 20 anniversaries that appear in the "On this day" section of the Main Page. To suggest a new item, in most cases, you can be bold and edit this page. Please read the selected anniversaries guidelines before making your edit. However, if your addition might be controversial or on a day that is or will soon be on the Main Page, please post your suggestion on the talk page instead.

Please note that the events listed on the Main Page are chosen based more on relative article quality and to maintain a mix of topics, not based solely on how important or significant their subjects are. Only four to five events are posted at a time and thus not everything that is "most important and significant" can be listed. In addition, an event is generally not posted this year if it is also the subject of the scheduled featured article or picture of the day.

To report an error when this appears on the Main Page, see Main Page errors. Please remember that this list defers to the supporting articles, so it is best to achieve consensus and make any necessary changes there first.

← April 19	April 21 →

Staging area

Images

• 
  Pierre Trudeau
• 
  Claude Bernard
• Louis Pasteur (requires undeletion)
  Louis Pasteur (requires undeletion)
• 
  Louis Pasteur
• 
  René Caillié
• 
  Ruins of the Ludlow colony
• 
  Portrait of Oliver Cromwell by Samuel Cooper
• 
  Red Army Faction logo, showing a Heckler & Koch MP5 submachine gun on top of a red star, overlaid with the letters "RAF"
• 
  Billie Holiday
• 
  Pope Leo XIII
• 
  Enoch Powell
• 
  Danica Patrick
• 
  Fernando Lugo

Ineligible

Blurb	Reason
1303 – Pope Boniface VIII issued a bull establishing what is now Sapienza University of Rome, today one of the largest universities in Europe.	refimprove section
1653 – Oliver Cromwell dissolved the Rump Parliament of the Commonwealth of England by force, eventually replacing it with the Barebone's Parliament.	refimprove section
1792 – After Foreign Minister Charles François Dumouriez presented the French Legislative Assembly with a long list of grievances against Austria, France declared war to begin the French Revolutionary Wars.	refimprove section
1862 – French chemist Louis Pasteur and physiologist Claude Bernard completed the first test on pasteurization.	date not in article; Pasteur listed on Sept 28 (death date); fact not in Bernard article
1884 – Pope Leo XIII published the encyclical Humanum genus, denouncing Freemasonry as well as a number of beliefs and practices purportedly associated with it such as popular sovereignty and the separation of church and state.	lots of assorted inline maintenance tags
1908 – The inaugural season of the New South Wales Rugby League premiership began with nine teams competing in Australia's first Rugby league football competition.	Season: refimprove section; NSWRL: refimprove
1912 – Fenway Park in Boston, Massachusetts, and Tiger Stadium in Detroit, Michigan, were opened.	Fenway: refimprove section
1998 – The violent German revolutionary group known as the Red Army Faction announced that it had dissolved.	refimprove section

Eligible

• 1537 – Bacatá, the main settlement of the Muisca Confederation in present-day Colombia, was conquered by Spanish conquistadors led by Gonzalo Jiménez de Quesada.
• 1657 – Anglo-Spanish War: The English navy sank much of a Spanish treasure fleet at the Battle of Santa Cruz de Tenerife off the Canary Islands, but was unable to capture the treasure.
• 1809 – War of the Fifth Coalition: Commanded by Napoleon, Franco-German forces defeated a reinforced Austrian corps at the Battle of Abensberg.
• 1828 – French explorer René Caillié reached Timbuktu in present-day Mali, and later received a 9,000-franc prize from the Société de Géographie for being the first European to return with a description of the city.
• 1914 – A fire and a gun battle between the Colorado National Guard and striking coal miners led to 17 deaths in the Ludlow Massacre.
• 1939 – Adolf Hitler's 50th birthday was celebrated as a national holiday in Nazi Germany.
• 1939 – Billie Holiday recorded the song "Strange Fruit", which later became an emblem of the civil rights movement.
• 1968 – Pierre Trudeau was sworn in as prime minister of Canada, succeeding Lester B. Pearson.
• 1968 – Enoch Powell (pictured), a British Conservative member of Parliament, made a controversial speech in opposition to immigration and anti-discrimination legislation, resulting in his removal from the shadow cabinet.
• 1978 – Korean Air Lines Flight 902 was shot down after violating Soviet airspace and was forced to make an emergency landing.
• 1999 – Students Eric Harris and Dylan Klebold carried out a massacre at Columbine High School, killing 13 people before committing suicide.
• 2004 – An incomplete tunnel leading to Singapore's Nicoll Highway MRT station collapsed that led to four deaths and the station's relocation.
• 2008 – American racing driver Danica Patrick won the Indy Japan 300, becoming the first woman to win an IndyCar auto race.
• 2008 – Fernando Lugo became the first candidate not from the Colorado Party candidate to be elected President of Paraguay in 61 years.
• Born/died this day: | Cædwalla of Wessex |d|689| Elizabeth Barton|d|1534| William Bedloe|b|1650| David Brainerd|b|1718| John Abernethy|d|1831| Paul Poiret|b|1879| Dave Bancroft|b|1891| Frances Ames|b|1920| Elmer Gedeon|d|1944| Vjekoslav Luburić|d|1969| Nina Davuluri|b|1989| Kojo Laing|d|2017

April 20: First day of Ridván (Baháʼí Faith, 2024); 420 (cannabis culture)

Vädersolstavlan

• 1535 – Sun dogs were observed over Stockholm, Sweden, inspiring the painting Vädersolstavlan (depicted), the oldest coloured depiction of the city.
• 1818 – Four days after the Court of King's Bench upheld an English murder suspect's right to a trial by battle in Ashford v Thornton, the plaintiff declined to fight, allowing the defendant to go free.
• 1942 – World War II: German and Italian forces began a large-scale counter-insurgency operation in occupied Yugoslavia.
• 1968 – South African Airways Flight 228 crashed shortly after take-off from Windhoek in South West Africa, resulting in 123 deaths.
• 2010 – An explosion on Deepwater Horizon, an offshore rig in the Gulf of Mexico, resulted in the largest marine oil spill in history.

• Peter Bartholomew (d. 1099)
• Allegra Byron (d. 1822)
• Toller Cranston (b. 1949)

More anniversaries:

• April 19
• April 20
• April 21