Editing April 21 (section)

===1901–present===
*[[1914]] &ndash; [[Ypiranga incident]]: A German arms shipment to Mexico is intercepted by the U.S. Navy near [[Veracruz (city)|Veracruz]].
*[[1918]] &ndash; [[World War I]]: [[German Empire|German]] fighter ace [[Manfred von Richthofen]], better known as "The Red Baron", is shot down and killed over [[Vaux-sur-Somme]] in [[French Third Republic|France]].
*[[1926]] &ndash; [[Al-Baqi'|Al-Baqi cemetery]], former site of the mausoleum of [[The Twelve Imams|four Shi'a Imams]], is [[Demolition of al-Baqi|leveled to the ground]] by [[Wahhabism|Wahhabis]].
*[[1934]] &ndash; The "Surgeon's Photograph", the most famous photo allegedly showing the [[Loch Ness Monster]], is published in the ''[[Daily Mail]]'' (in 1994, it is revealed to be a hoax).<ref name="museumofhoaxes_nessie">{{cite web |url=http://www.museumofhoaxes.com/nessie.html |title=The Loch Ness Monster and the Surgeon's Photo |publisher=Museumofhoaxes.com |access-date=28 May 2009 |archive-date=6 August 2014 |archive-url=https://web.archive.org/web/20140806122015/http://www.museumofhoaxes.com/nessie.html |url-status=live }}</ref>
*[[1945]] &ndash; [[World War II]]: [[Soviet Union|Soviet]] forces south of Berlin at [[Zossen]] attack the [[Maybach I and II|German High Command]] headquarters.
*[[1946]] &ndash; The [[National Weather Service|U.S. Weather Bureau]] records that a [[List of United States tornadoes in 1946#April 21 event|tornado]] which struck [[Timber Lake, South Dakota]] was {{convert|4|mi|km}}, among [[Tornado records#Largest path width|the widest tornadoes on record]].<ref>{{cite journal |journal=Monthly Weather Review |date=1 April 1946 |volume=74 |issue=4 |page=73 |doi=10.1175/1520-0493(1946)074<0073:SLSFA>2.0.CO;2 |doi-access=free |title=Severe Local Storms for April 1946 |bibcode=1946MWRv...74...73. }}</ref>
*[[1948]] &ndash; [[United Nations Security Council Resolution 47]] relating to [[Kashmir conflict]] is adopted.
*[[1950]] &ndash; The [[Nainital wedding massacre]] occurs, killing 22 members of the Harijan caste.<ref>[https://news.google.com/newspapers?id=529YAAAAIBAJ&sjid=EPgDAAAAIBAJ&pg=1389,1304611&dq= 22 guests slain], ''[[The Bend Bulletin]]'' (21 April 1950)</ref><ref>[https://newspaperarchive.com/ogden-standard-examiner/1950-04-21/ 22 guests slain as wedding held], ''[[The Ogden Standard-Examiner]]'' (21 April 1950)</ref><ref>[https://web.archive.org/web/20121105104424/http://pqasb.pqarchiver.com/latimes/access/423532671.html?dids=423532671:423532671&FMT=CITE&FMTS=CITE:AI&type=historic&date=Apr+22%2C+1950&author=&pub=Los+Angeles+Times&desc=Studio+Electrician+Loses+Paternity+Suit+Verdict&pqatl=google Drunk Gurkha Kills 22], ''[[Los Angeles Times]]'' (22 April 1950) </ref><ref>[https://newspaperarchive.com/huntingdon-daily-news/1950-04-22/page-5 Murders 22 at wedding], ''[[The Huntingdon Daily News]]'' (22 April 1950)</ref>
*[[1952]] &ndash; [[Secretary's Day]] (now Administrative Professionals' Day) is first celebrated.
*[[1958]] &ndash; [[United Air Lines Flight 736]] collides with a [[United States Air Force]] fighter jet near [[Arden, Nevada]] in what is now [[Enterprise, Nevada]].<ref>{{cite news|title=Fatal Las Vegas crash in 1958 led to modern air safety system|newspaper=Las Vegas Review-Journal|author=Henry Brean|date=April 20, 2018|url=https://www.reviewjournal.com/local/local-las-vegas/fatal-las-vegas-crash-in-1958-led-to-modern-air-safety-system/|access-date=2020-04-05}}</ref>
*[[1960]] &ndash; [[Brasília]], Brazil's capital, is officially inaugurated. At 09:30, the Three Powers of the Republic are simultaneously transferred from the old capital, [[Rio de Janeiro]].
*[[1962]] &ndash; The [[Century 21 Exposition|Seattle World's Fair]] (Century 21 Exposition) opens. It is the first [[World's Fair]] in the United States since World War II.
*[[1963]] &ndash; The first election of the [[Universal House of Justice]] is held, marking its establishment as the supreme governing institution of the [[Baháʼí Faith]].
*[[1964]] &ndash; A [[Transit (satellite)|Transit-5bn]] satellite fails to reach orbit after launch; as it re-enters the atmosphere, {{convert|2.1|lb}} of radioactive [[plutonium]] in its [[Systems Nuclear Auxiliary Power Program|SNAP]] [[Radioisotope thermoelectric generator|RTG]] power source is widely dispersed.
*[[1965]] &ndash; The [[1964 New York World's Fair|1964–1965 New York World's Fair]] opens for its second and final season.
*[[1966]] &ndash; [[Rastafari|Rastafari movement]]: [[Haile Selassie]] of [[Ethiopia]] visits [[Jamaica]], an event now celebrated as [[Grounation Day]].
*[[1967]] &ndash; A few days before the [[general election]] in Greece, Colonel [[Georgios Papadopoulos|George Papadopoulos]] leads a [[coup d'état]], establishing a [[Greek junta|military regime]] that lasts for seven years.
*[[1972]] &ndash; Astronauts [[John Young (astronaut)|John Young]] and [[Charles Duke]] fly [[Apollo 16]]'s [[Apollo Lunar Module]] to the Moon's surface, the fifth NASA [[Apollo Program]] crewed lunar landing.<ref>[https://www.lpi.usra.edu/lunar/missions/apollo/apollo_16/ Landing site/]. Retrieved 25 March 2019</ref>
*[[1975]] &ndash; [[Vietnam War]]: President of [[South Vietnam]] [[Nguyễn Văn Thiệu]] flees [[Ho Chi Minh City|Saigon]], as [[Xuân Lộc district|Xuân Lộc]], the last South Vietnamese outpost blocking a direct [[North Vietnam]]ese assault on Saigon, [[Battle of Xuân Lộc|falls]].
*[[1977]] &ndash; ''[[Annie (musical)|Annie]]'' opens on [[Broadway theatre|Broadway]].
*[[1982]] &ndash; [[Baseball]]: [[Rollie Fingers]] of the [[Milwaukee Brewers]] becomes the first [[pitcher]] to record 300 saves.
*[[1985]] &ndash; The compound of the militant group [[The Covenant, The Sword, and the Arm of the Lord]] surrenders to federal authorities in Arkansas after a two-day government siege. 
*[[1987]] &ndash; The [[Liberation Tigers of Tamil Eelam|Tamil Tigers]] are blamed for a [[car bomb]] that detonates in the [[Sri Lanka]]n capital city of [[Colombo]], killing 106 people.
*[[1989]] &ndash; [[1989 Tiananmen Square protests and massacre|Tiananmen Square protests of 1989]]: In Beijing, around 100,000 students gather in [[Tiananmen Square]] to commemorate Chinese reform leader [[Hu Yaobang]].
*[[1993]] &ndash; The Supreme Court in [[La Paz]], Bolivia, sentences former dictator [[Luis García Meza]] to 30 years in jail without parole for murder, theft, fraud and violating the constitution.
*[[2004]] &ndash; Five suicide car bombers [[21 April 2004 Basra bombings|target police stations]] in and around [[Basra]], killing 74 people and wounding 160.
*[[2010]] &ndash; The controversial [[Kharkiv Pact]] (Russian Ukrainian Naval Base for Gas Treaty) is signed in [[Kharkiv]], Ukraine, by [[Ukrainian President]] [[Viktor Yanukovych]] and [[Russian President]] [[Dmitry Medvedev]]; it was unilaterally terminated by Russia on March 31, 2014.
*[[2012]] &ndash; Two trains are involved in a [[Amsterdam Westerpark train collision|head-on collision]] near [[Sloterdijk, Amsterdam]], in the Netherlands, killing one person and injuring 116 others.<ref>{{Cite news |date=2012-04-22 |title=Dutch train crash: Woman dies of her injuries |language=en-GB |work=BBC News |url=https://www.bbc.com/news/world-europe-17807697 |access-date=2023-04-19}}</ref>
*[[2014]] &ndash; The American city of [[Flint, Michigan]] switches its water source to the [[Flint River (Michigan)|Flint River]], beginning the ongoing [[Flint water crisis]] which has caused [[lead poisoning]] in up to 12,000 people, and at least 12 deaths from [[Legionnaires' disease]], ultimately leading to criminal indictments against 15 people, five of whom have been charged with [[involuntary manslaughter]].
*[[2019]] &ndash; [[2019 Sri Lanka Easter bombings|Eight bombs explode]] at churches, hotels, and other locations in [[Sri Lanka]] on [[Easter Sunday]], killing at least 269.<ref>{{cite news |author=Burke |first=Jason |date=2019-04-21 |title='There was utter chaos': Sri Lanka left reeling after wave of bombings |url=https://www.theguardian.com/world/2019/apr/21/there-was-utter-chaos-sri-lanka-left-reeling-after-wave-of-bombings |access-date=2019-04-22 |newspaper=The Guardian}}</ref>
*[[2021]] &ndash; [[Indonesian Navy]] submarine [[KRI Nanggala (402)]] sinks in the [[Bali Sea]] during a military drill, killing all 53 on board.<ref name="reuters.search">{{Cite web|last1=Beo Da Costa|first1=Agustinus|last2=Lamb|first2=Kate|date=21 April 2021|editor-last=Petty|editor-first=Martin|title=Indonesian navy checking on submarine after failure to report back from exercise|url=https://www.reuters.com/world/asia-pacific/indonesian-navy-checking-submarine-after-failure-report-back-exercise-2021-04-21/|url-status=live|archive-url=https://web.archive.org/web/20210421093435/https://www.reuters.com/world/asia-pacific/indonesian-navy-checking-submarine-after-failure-report-back-exercise-2021-04-21/|archive-date=21 April 2021|access-date=21 April 2021|website=[[Reuters]]}}<!-- note: source states spokesperson announces failure to report results but does not identify spokesperson --></ref>