Editing April 20 (section)

===1901–present===
*[[1902]] &ndash; [[Pierre Curie|Pierre]] and [[Marie Curie]] refine [[radium chloride]].
*[[1908]] &ndash; Opening day of competition in the [[New South Wales Rugby League]].<ref>{{cite book|title= The best ever Australian Sports Writing|last= Cunneen|first= Chris|year= 2001|publisher= Black Inc.|location= Australia|isbn= 1-86395-266-7|page= 321|url= https://books.google.com/books?id=66OBschGE_YC|access-date= 19 February 2011}}</ref>
*[[1914]] &ndash; Nineteen men, women, and children participating in a strike are killed in the [[Ludlow Massacre]] during the [[Colorado Coalfield War]].<ref>{{cite book|last=Rees|first=Jonathan|chapter=Ludlow Massacre|title=The Oxford Encyclopedia of American Business, Labor, and Economic History. Volume 1: Abra to Mutu|editor-last=Dubofsky|editor-first=Melvyn|location=Oxford, UK|publisher=Oxford University Press|date=2013|isbn=978-0-19-999304-8|url=https://books.google.com/books?id=D-NMAgAAQBAJ|pages=483–484}}</ref>
*[[1918]] &ndash; [[Manfred von Richthofen]], a.k.a. The Red Baron, shoots down his 79th and 80th victims, his final victories before his death the following day.
*[[1922]] &ndash; The [[Soviet Union|Soviet]] government creates [[South Ossetian Autonomous Oblast]] within [[Georgian Soviet Socialist Republic|Georgian SSR]].
*[[1945]] &ndash; [[World War II]]: U.S. troops capture [[Leipzig]], Germany, only to later cede the city to the [[Soviet Union]].
*  1945 &ndash; World War II: [[Führerbunker]]: On his 56th birthday [[Adolf Hitler]] makes his last trip to the surface to award [[Iron Cross]]es to boy soldiers of the [[Hitler Youth]].
*  1945 &ndash; Twenty Jewish children used in [[Nazi human experimentation|medical experiments]] at [[Neuengamme concentration camp|Neuengamme]] are killed in the basement of the [[Bullenhuser Damm]] school.
*[[1946]] &ndash; The [[League of Nations]] officially [[dissolution (law)|dissolves]], giving most of its power to the [[United Nations]].
*  [[1949]] &ndash; [[Amethyst incident]]: The [[People's Liberation Army]] attacks {{HMS|Amethyst|F116}} travelling to the British embassy in [[Nanjing]] during the [[Chinese Civil War]].<ref>{{Cite journal |last=Murfett |first=Malcolm H. |date=May 1991 |title=A Pyrrhic Victory: HMS Amethyst and the Damage to Anglo-Chinese Relations in 1949 |journal=[[War & Society]] |language=en |volume=9 |issue=1 |pages=121–140 |doi=10.1179/072924791791202396 |issn=0729-2473}}</ref>
*[[1961]] &ndash; [[Cold War]]: Failure of the [[Bay of Pigs Invasion]] of US-backed Cuban exiles against [[Cuba]].
*[[1968]] &ndash; English politician [[Enoch Powell]] makes his controversial [[Rivers of Blood speech|"Rivers of Blood" speech]].<ref>{{cite book|author1=Anthony F Heath|author2=Sin Yi Cheung|author3=Shawna N. Smith|title=Unequal Chances: Ethnic Minorities in Western Labour Markets|url=https://books.google.com/books?id=0ahnAAAAMAAJ|date=25 October 2007|publisher=OUP/British Academy|isbn=978-0-19-726386-0|page=512}}</ref>
*  1968   &ndash; [[South African Airways Flight 228]] crashes near [[Hosea Kutako International Airport|J.G. Strijdom Airport]] in [[South West Africa]] (now Hosea Kutako International Airport in [[Namibia]]), killing 123 people.<ref>{{Cite web |last=Ranter |first=Harro |title=ASN Aircraft accident Boeing 707-344C ZS-EUW Windhoek-Strijdom International Airport (WDH) |url=https://aviation-safety.net/database/record.php?id=19680420-0 |access-date=2022-04-19 |website=aviation-safety.net |publisher=[[Aviation Safety Network]]}}</ref>
*[[1972]] &ndash; [[Apollo program]]: [[Apollo 16]] [[Apollo Lunar Module|Lunar Module]], commanded by [[John Young (astronaut)|John Young]] and piloted by [[Charles Duke]], lands on the Moon.
*[[1998]] &ndash; [[Air France Flight 422]] crashes after taking off from [[El Dorado International Airport]] in [[Bogotá]], Colombia, killing all 53 people on board.<ref>{{Cite web |last=Ranter |first=Harro |title=ASN Aircraft accident Boeing 727-230 HC-BSU Bogotá-Eldorado Airport (BOG) |url=https://aviation-safety.net/database/record.php?id=19980420-0 |access-date=2019-04-17 |website=aviation-safety.net |publisher=Aviation Safety Network}}</ref>
*[[1999]] &ndash; [[Columbine High School massacre]]: [[Eric Harris and Dylan Klebold]] kill 14 people and injure 23 others before committing suicide at [[Columbine High School]] in [[Columbine, Colorado]].<ref>{{cite web |last1=Vigdor |first1=Neil |date=March 13, 2025 |title=Death Toll in 1999 Columbine School Shooting Climbs to 14 With Homicide Ruling |url=https://www.nytimes.com/2025/03/13/us/columbine-school-shooting-death-toll.html |website=[[The New York Times]] |access-date=April 20, 2025 |archive-url=https://web.archive.org/web/20250410141149/https://www.nytimes.com/2025/03/13/us/columbine-school-shooting-death-toll.html |archive-date=April 10, 2025}}</ref>
*[[2004]] - The [[Nicoll Highway]] in [[Singapore]] [[Nicoll Highway collapse|collapsed]], killing four workers.<ref>{{Cite web |last=Singapore |first=National Library Board |title=Nicoll Highway collapse |url=https://www.nlb.gov.sg/main/article-detail?cmsuuid=7a60c2bc-c72a-4f4d-b447-a68e7ad7ee00 |access-date=2024-04-20 |website=www.nlb.gov.sg |language=en}}</ref>
*[[2007]] &ndash; [[Johnson Space Center shooting]]: William Phillips barricades himself with a [[handgun]] in [[NASA]]'s [[Johnson Space Center]] in [[Houston, Texas]] before killing a male hostage and himself.<ref>{{Cite web |last= |first= |date=April 20, 2007 |title=Gunman kills hostage, self at NASA center |url=https://www.nbcnews.com/id/wbna18233965 |url-status=live |archive-url=https://web.archive.org/web/20230806205611/https://www.nbcnews.com/id/wbna18233965 |archive-date=August 6, 2023 |access-date=August 6, 2023 |website=[[NBC News]] |language=en}}</ref>
*[[2008]] &ndash; [[Danica Patrick]] wins the [[Indy Japan 300]] becoming the first female driver in history to win an [[American Championship car racing|Indy car]] race.<ref>{{Cite news|url=http://www.cbc.ca/sports/danica-patrick-makes-history-with-indy-japan-300-win-1.715905|title=Danica Patrick makes history with Indy Japan 300 win|date=April 21, 2008|publisher=[[CBC News]]|access-date=January 1, 2018|archive-url=https://archive.today/20180106094637/http://www.cbc.ca/sports/danica-patrick-makes-history-with-indy-japan-300-win-1.715905|archive-date=January 6, 2018|url-status=live|df=mdy-all}}</ref>
*[[2010]] &ndash; The ''[[Deepwater Horizon]]'' drilling rig [[Deepwater Horizon explosion|explodes]] in the Gulf of Mexico, killing eleven workers and beginning an [[Deepwater Horizon oil spill|oil spill that would last six months]].
*[[2012]] &ndash; One hundred twenty-seven people are killed when a [[Bhoja Air Flight 213|plane crashes]] in a residential area near the [[Benazir Bhutto International Airport]] near [[Islamabad]], Pakistan.
*[[2013]] &ndash; A 6.6-[[Moment magnitude scale|magnitude]] [[2013 Lushan earthquake|earthquake]] strikes [[Lushan County, Sichuan|Lushan County]], [[Ya'an]], in China's [[Sichuan]] province, killing at least 193 people and injuring thousands.
*[[2015]] &ndash; Ten people are killed in a [[2015 Garowe attack|bomb attack]] on a convoy carrying food supplies to a [[United Nations]] compound in [[Garowe]] in the Somali region of [[Puntland]].
*[[2020]] &ndash; For the first time in history, [[Price of oil|oil prices]] drop [[Negative pricing|below zero]], an effect of the [[2020 Russia–Saudi Arabia oil price war|2020 Russia-Saudi Arabia oil price war]].<ref>{{cite news|url=https://www.marketwatch.com/story/about-150-years-of-oil-price-history-in-one-chart-illustrates-crudes-spectacular-plunge-below-0-a-barrel-2020-04-22  |title=About 150-years of oil-price history in one chart illustrates crude's spectacular plunge below $0 a barrel     |author=Mark DeCambre  |agency=  |work=Market Watch  |date=April 22, 2020  }}</ref>
*[[2021]] &ndash; ''[[State of Minnesota v. Derek Michael Chauvin]]'': [[Derek Chauvin]] is found guilty of all charges in the [[murder of George Floyd]] by the [[District Court of Minnesota|Fourth Judicial District Court of Minnesota]].<ref>{{cite news|first1=Jonathan|last1=Allen|first2=Nathan|last2=Layne|first3=Gabriella|last3=Borter|date=April 21, 2021|title=Minneapolis jury convicts ex-policeman Derek Chauvin of murdering George Floyd|url=https://www.reuters.com/world/us/jurors-resume-deliberations-derek-chauvin-murder-trial-2021-04-20/|work=[[Reuters]]|language=en|access-date=April 25, 2022}}</ref>
*[[2023]] &ndash; [[SpaceX Starship|SpaceX's Starship]] rocket, the largest and most powerful rocket ever built, launches for the first time. It explodes four minutes into flight.<ref>{{Cite news| last1 = Berger | first1 = Eric |date=2023-04-20 |title=So what was that? Was Starship’s launch a failure or a success? |work=[[Ars Technica]] | publisher = [[Condé Nast]] | location = New York | url= https://arstechnica.com/science/2023/04/so-what-was-that-was-starships-launch-a-failure-or-a-success/|access-date=2025-04-20  |archive-url = https://web.archive.org/web/20230420173954/https://arstechnica.com/science/2023/04/so-what-was-that-was-starships-launch-a-failure-or-a-success/| archive-date=2023-04-20 | url-status = live}}</ref>