Editing December 21 (section)

===1901–present===
*[[1907]] &ndash; The [[Chilean Army]] [[Santa María School massacre|commits a massacre]] of at least 2,000 striking [[Sodium nitrate|saltpeter]] miners in [[Iquique]], [[Chile]].<ref>{{Cite book|title=La Masacre de la Escuela Santa María de Iquique: Mirada Histórica desde la Cámara de Diputados|last=Hoehn|first=Marek|publisher=Biblioteca del Congreso Nacional de Chile|year=2007|isbn=978-956-7629-04-6|page=110|editor-last=Vásquez|editor-first=David|language=es|chapter=Una visión comparativa sobre la huelga de Santa María de Iquique y el legado de los movimientos obreros de la época|quote=Ya es sabido que dicha huelga culminó en la masacre de más de dos mil obreros en la escuela Santa María}}</ref>
*[[1910]] &ndash; [[Pretoria Pit disaster|An underground explosion]] at the [[Hulton Colliery Company|Hulton Bank Colliery]] No. 3 Pit in [[Over Hulton]], [[Westhoughton]], England, kills 344 miners.
*[[1913]] &ndash; [[Arthur Wynne]]'s "word-cross", the first [[crossword]] puzzle, is published in the ''[[New York World]]''.
*[[1919]] &ndash; American [[anarchism|anarchist]] [[Emma Goldman]] is deported to Russia.
*[[1923]] &ndash; United Kingdom and [[Nepal]] formally sign an agreement of friendship, called the [[Nepal–Britain Treaty of 1923]], which superseded the [[Treaty of Sugauli]] signed in 1816.
*[[1934]] &ndash; ''[[Lieutenant Kijé (Prokofiev)|Lieutenant Kijé]]'', one of [[Sergei Prokofiev]]'s best-known works, premiered.<ref>{{cite book|last= MacDonald|first= Laurence E.|title= The Invisible Art of Film Music: A Comprehensive History|url= https://books.google.com/books?id=e0NYYHWtz6sC|publisher= The Scarecrow Press|location= New York|year= 2013|page=35|isbn= 978-0-8108-8397-0}}</ref>
*[[1936]] &ndash; First flight of the [[Junkers Ju 88]] multi-role combat aircraft.
*[[1937]] &ndash; ''[[Snow White and the Seven Dwarfs (1937 film)|Snow White and the Seven Dwarfs]]'', the world's first full-length [[Animation|animated]] feature, premieres at the [[Carthay Circle Theatre]].
*[[1941]] &ndash; [[World War II]]: A [[Thailand in World War II|Thai-Japanese Pact of Alliance]] is signed.
*[[1946]] &ndash; An 8.1 [[Moment magnitude scale|M<sub>w</sub>]] [[1946 Nankai earthquake|earthquake]] and subsequent [[tsunami]] in [[Nankaidō]], Japan, kills over 1,300 people and destroys over 38,000 homes.
*[[1963]] &ndash; [[Bloody Christmas (1963)|"Bloody Christmas"]] begins in Cyprus, ultimately resulting in the displacement of 25,000–30,000 [[Turkish Cypriots]] and destruction of more than 100 villages.
*[[1965]] &ndash; [[International Convention on the Elimination of All Forms of Racial Discrimination]] is adopted.
*[[1967]] &ndash; [[Louis Washkansky]], the first man to undergo a human-to-human [[Heart transplantation|heart transplant]], dies in [[Cape Town]], South Africa, having lived for 18 days after the transplant.
*[[1968]] &ndash; [[Apollo program]]: [[Apollo 8]] is launched from the [[Kennedy Space Center]], placing its crew on a [[Moon|lunar]] trajectory for the first visit to another celestial body by humans.
*[[1970]] &ndash; First flight of [[Grumman F-14 Tomcat|F-14]] multi-role combat aircraft.
*[[1973]] &ndash; The [[Geneva Conference (1973)|Geneva Conference]] on the [[Arab–Israeli conflict]] opens.
*[[1979]] &ndash; [[Lancaster House Agreement]]: An independence agreement for [[Rhodesia]] is signed in London by [[Peter Carington, 6th Baron Carrington|Lord Carrington]], Sir [[Ian Gilmour, Baron Gilmour of Craigmillar|Ian Gilmour]], [[Robert Mugabe]], [[Joshua Nkomo]], Bishop [[Abel Muzorewa]] and S.C. Mundawarara.
*[[1988]] &ndash; A bomb explodes on board [[Pan Am Flight 103]] over [[Lockerbie]], [[Dumfries and Galloway]], Scotland, killing 270.<ref>{{cite web |title=Lockerbie bombing suspect in US custody |url=https://www.bbc.co.uk/news/uk-scotland-63933837 |website=BBC News |access-date=11 December 2022 |date=11 December 2022}}</ref> This is to date the deadliest air disaster to occur on British soil. 
*  1988   &ndash; The first flight of [[Antonov An-225 Mriya]], the largest aircraft in the world.
*[[1991]] &ndash; [[Dissolution of the Soviet Union]]: The leaders of 11 now effectively autonomous Soviet republics sign the [[Alma-Ata Protocol]] establishing the [[Commonwealth of Independent States]] in place of the collapsing [[Soviet Union]].<ref>{{Cite book |last=Fedor |first=Helen |title=Belarus and Moldova: Country Studies |publisher=[[Federal Research Division]] |year=1995 |isbn=0844408492 |edition=1st |location=Washington, D.C. |page=195 |language=en}}</ref>
*[[1992]] &ndash; A [[Netherlands|Dutch]] [[McDonnell Douglas DC-10|DC-10]], flight [[Martinair Flight 495|Martinair MP 495]], crashes at [[Faro Airport]], killing 56.
*[[1995]] &ndash; The city of [[Bethlehem]] passes from [[Israel]]i to [[Palestinian National Authority|Palestinian]] control.
*[[1999]] &ndash; The [[Civil Guard (Spain)|Spanish Civil Guard]] intercepts a van loaded with 950&nbsp;kg of explosives that [[ETA (separatist group)|ETA]] intended to use to blow up [[Torre Picasso]] in [[Madrid]], Spain.
*  1999   &ndash; [[Cubana de Aviación Flight 1216]] overshoots the runway at [[La Aurora International Airport]], killing 18.<ref>{{Cite web|url=https://aviation-safety.net/database/record.php?id=19991221-0|title=ASN Aircraft accident McDonnell Douglas DC-10-30 F-GTDI Guatemala City-La Aurora Airport (GUA)|last=Ranter|first=Harro|website=aviation-safety.net|access-date=2019-09-20}}</ref>
*[[2004]] &ndash; [[Iraq War]]: A [[suicide attack|suicide bomber]] [[2004 Forward Operating Base Marez bombing|kills 22]] at the [[forward operating base]] next to the main U.S. military airfield at [[Mosul]], [[Iraq]], the single deadliest suicide attack on American soldiers in Iraq.
*[[2012]] &ndash; [[2012 phenomenon]]: Festivities are held in parts of Mesoamerica to commemorate the conclusion of b’ak’tun 13, a roughly 5,126-year-long cycle in the [[Mesoamerican Long Count Calendar]] whose passing many [[New Age]] spiritualists had earlier held to portend a variety of cataclysmic or transformative events.<ref>{{Cite news |last=Alper |first=Alexandra |date=21 December 2012 |title=Celebrations in Mexico as world survives Maya "end of days" |work=[[Reuters]] |url=https://www.reuters.com/article/idUSBRE8BJ16Q/ |access-date=21 December 2023}}</ref>
*[[2020]] &ndash; A [[great conjunction]] of [[Jupiter]] and [[Saturn]] occurs, with the two planets separated in the sky by 0.1 degrees. This is the closest conjunction between the two planets since 1623.<ref>{{Cite web|title=See the Great Conjunction of Jupiter and Saturn, 21 December 2020|url=https://www.skyatnightmagazine.com/advice/skills/great-conjunction-jupiter-saturn|access-date=2020-11-29|website=BBC Sky at Night Magazine}}</ref>
*[[2023]] &ndash; Fourteen people are killed and 25 others injured during [[2023 Prague shooting|a mass shooting]] at [[Charles University]] in [[Prague]], [[Czech Republic]]. The perpetrator, a student at the university, kills himself after police arrived; he also killed his father before the shooting.<ref>{{cite web |title=A lone gunman opens fire in a Prague university, killing 15 people and injuring 24 |url=https://apnews.com/article/prague-shooting-dead-injured-9a383bc6919c1b0d929cf06aa4818341 |website=AP News |date=21 December 2023 |access-date=21 December 2023}}</ref>