Editing May 20 (section)

===1901–present===
*[[1902]] &ndash; [[Cuba]] gains independence from the United States. [[Tomás Estrada Palma]] becomes the country's first President.
*[[1927]] &ndash; [[Treaty of Jeddah (1927)|Treaty of Jeddah]]: The United Kingdom recognizes the [[sovereignty]] of King [[Ibn Saud]] in the Kingdoms of [[Hejaz]] and [[Najd|Nejd]], which later merge to become the Kingdom of [[Saudi Arabia]].
*[[1927]] &ndash; [[Charles Lindbergh]] takes off for Paris from Roosevelt Field in Long Island, N.Y., aboard the [[Spirit of St. Louis]] on the first nonstop solo flight across the Atlantic Ocean, landing {{frac|33|1|2}} hours later.<ref>{{cite web| title = Charles Lindbergh: An American Aviator | url=http://www.charleslindbergh.com/ | website = www.charleslindbergh.com/ | access-date = 19 May 2022}}</ref> 
*[[1932]] &ndash; [[Amelia Earhart]] takes off from [[Newfoundland (island)|Newfoundland]] to begin the world's first solo nonstop flight across the Atlantic Ocean by a female pilot, landing in Ireland the next day.
*[[1940]] &ndash; [[The Holocaust]]: The first prisoners arrive at a [[Auschwitz concentration camp|new concentration camp at Auschwitz]].
*[[1941]] &ndash; World War II: [[Battle of Crete]]: [[Nazi Germany|German]] [[Fallschirmjäger (World War II)|paratroops]] invade [[Crete]].
*[[1943]] &ndash; The [[Luttra Woman]], a [[bog body]] from the Early [[Neolithic]] period ([[Radiocarbon dating|radiocarbon-dated]] {{circa|3928–3651 BC}}),<ref>{{cite journal |title=Early Neolithic human bog finds from Falbygden, western Sweden: New isotopic, osteological and histological investigations |first1=Karl-Göran |last1=Sjögren |first2=Torbjörn |last2=Ahlström |first3=Malou |last3=Blank |first4=T. Douglas |last4=Price |first5=Karin Margarita |last5=Frei |journal=Journal of Neolithic Archaeology |issue=19 |date=2017 |pages=101 |doi=10.12766/jna.2017.4 |doi-access=free |issn=2197-649X |publisher=Institute of Prehistoric and Protohistoric Archaeology at [[Kiel University]] |location=Germany}}</ref> was discovered near [[Luttra]], Sweden.<ref>{{cite web |url=https://www.falkoping.se/falbygdens-museum/upptack-falbygden/historien-om-hallonflickan |title=Historien om Hallonflickan |trans-title=Story of the Raspberry Girl |lang=sv |access-date=2023-01-23 |first=Cecilia |last=Jensen |publisher=Falbygdens Museum |date=2021 |archive-date=26 August 2022 |location=[[Falköping]] |archive-url=https://web.archive.org/web/20220826223842/https://www.falkoping.se/falbygdens-museum/upptack-falbygden/historien-om-hallonflickan |url-status=live}}</ref>
*[[1948]] &ndash; Generalissimo [[Chiang Kai-shek]] wins the [[1948 Chinese presidential election|1948 Republic of China presidential election]] and is sworn in as the first [[President of the Republic of China]] at [[Nanjing]].
*[[1949]] &ndash; In the United States, the Armed Forces Security Agency, the predecessor to the [[National Security Agency]], is established.
*[[1956]] &ndash; In [[Operation Redwing]], the first United States airborne [[hydrogen bomb]] is dropped over [[Bikini Atoll]] in the Pacific Ocean.
*[[1958]] &ndash; [[Capital Airlines Flight 300]] collides in mid-air with a [[United States Air Force]] [[Lockheed T-33]] over [[Brunswick, Maryland]], killing 12.<ref name="stpttm">{{cite news |date=21 May 1958 |title=AF jet, airliner collide; 12 killed |url=https://news.google.com/newspapers?id=99INAAAAIBAJ&sjid=RHYDAAAAIBAJ&pg=4935%2C5591 |work=St. Petersburg Times |location=(Florida) |page=1 |agency=Associated Press}}</ref>
*[[1964]] &ndash; [[Discovery of cosmic microwave background radiation|Discovery]] of the [[cosmic microwave background radiation]] by [[Robert Woodrow Wilson]] and [[Arno Penzias]].
*[[1965]] &ndash; One hundred twenty-one people are killed when [[Pakistan International Airlines Flight 705]] crashes at [[Cairo International Airport]].<ref>{{Cite web|last=Ranter|first=Harro|title=ASN Aircraft accident Boeing 720-040B AP-AMH Cairo International Airport (CAI)|url=https://aviation-safety.net/database/record.php?id=19650520-0|access-date=2022-02-19|website=aviation-safety.net|publisher=[[Aviation Safety Network]]}}</ref>
*[[1967]] &ndash; The [[Popular Movement of the Revolution]] [[political party]] is established in the [[Democratic Republic of the Congo]].
*[[1969]] &ndash; The [[Battle of Hamburger Hill]] in [[Vietnam]] ends.
*[[1971]] &ndash; In the [[Chuknagar massacre]], Pakistani forces massacre thousands, mostly Bengali Hindus.
*[[1980]] &ndash; In a [[1980 Quebec referendum|referendum]] in Quebec, the population rejects, with 60% of the vote, a government proposal to move towards independence from Canada.
*[[1983]] &ndash; First publications of the discovery of the [[HIV]] [[virus]] that causes [[AIDS]] in the journal ''[[Science (journal)|Science]]'' by a team of French scientists including [[Françoise Barré-Sinoussi]], [[Jean-Claude Chermann]], and [[Luc Montagnier]].<ref>{{Cite journal|last1=Barré-Sinoussi|first1=F.|last2=Chermann|first2=J. C.|last3=Rey|first3=F.|last4=Nugeyre|first4=M. T.|last5=Chamaret|first5=S.|last6=Gruest|first6=J.|last7=Dauguet|first7=C.|last8=Axler-Blin|first8=C.|last9=Vézinet-Brun|first9=F.|last10=Rouzioux|first10=C.|last11=Rozenbaum|first11=W.|last12=Montagnier|first12=L.|title=Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS) |journal=Science |volume=220 |issue=4599 |pages=868–871 |year=1983 |pmid=6189183 |doi=10.1126/science.6189183 |bibcode=1983Sci...220..868B}}</ref>
* 1983 &ndash; [[Church Street, Pretoria bombing|Church Street bombing]]: A car bomb planted by [[UMkhonto we Sizwe]] explodes on Church Street in South Africa's capital, [[Pretoria]], killing 19 people and injuring 217 others.
*[[1985]] &ndash; [[Radio Martí]], part of the [[Voice of America]] service, begins broadcasting to [[Cuba]].
*[[1989]] &ndash; The Chinese authorities declare martial law in the face of pro-[[democracy]] demonstrations, setting the scene for the [[Tiananmen Square massacre]].
*[[1990]] &ndash; The first post-[[communism|Communist]] presidential and parliamentary elections are held in [[Romania]].
*[[1996]] &ndash; [[LGBT rights in the United States|Civil rights]]: The [[Supreme Court of the United States]] rules in ''[[Romer v. Evans]]'' against a law that would have prevented any city, town or county in the state of [[Colorado]] from taking any legislative, executive, or judicial action to protect the rights of [[Homosexuality|gays and lesbians]].<ref>{{cite book|last=Hudson|first=David L.|title=Equal Protection: Documents Decoded|location=Santa Barbara, Calif.|publisher=ABC-CLIO|date=2018|isbn=9781440858048|url=https://books.google.com/books?id=nxVbDwAAQBAJ|page=179}}</ref>
*[[2002]] &ndash; The independence of [[East Timor]] is recognized by Portugal, formally ending 23 years of [[Indonesia]]n rule and three years of provisional UN administration (Portugal itself is the former [[Portuguese Empire|colonizer]] of East Timor until 1976).
*[[2009]] &ndash; An [[Indonesian Air Force]] [[Lockheed L-100 Hercules]] [[2009 Indonesian Air Force L-100 crash|crashes]] in [[Magetan Regency]], killing 99.<ref name="98killed">{{cite news |date=2009-05-20 |title=Indonesia says 98 killed in military plane crash |url=https://www.reuters.com/article/worldNews/idUSTRE54J0WC20090520 |url-status=live |archiveurl=https://web.archive.org/web/20090523110353/https://www.reuters.com/article/worldNews/idUSTRE54J0WC20090520 |archivedate=23 May 2009 |accessdate=2009-05-20 |work=[[Reuters]]}}</ref>
*[[2011]] &ndash; [[Mamata Banerjee]] is sworn in as the [[Chief Minister of West Bengal]], the first woman to hold this post.<ref name="BBC20110520">{{cite news |title=Mamata Banerjee sworn in as West Bengal chief minister |url=https://www.bbc.com/news/world-south-asia-13465915 |access-date=3 January 2021 |work=BBC News |date=20 May 2011}}</ref> 
*[[2012]] &ndash; At least 27 people are killed and 50 others injured when a [[2012 Northern Italy earthquakes|6.0-magnitude earthquake]] strikes northern Italy.
*[[2013]] &ndash; An [[Enhanced Fujita scale|EF5]] [[2013 Moore tornado|tornado]] strikes the [[Oklahoma City]] suburb of [[Moore, Oklahoma|Moore]], killing 24 people and injuring 377 others.
*[[2016]] &ndash; The government of [[Singapore]] authorised the controversial [[Capital punishment|execution]] of convicted murderer [[Kho Jabing]] for the murder of a Chinese construction worker despite the international pleas for clemency, notably from [[Amnesty International]] and the [[United Nations]].<ref>{{Cite web|date=20 May 2016|title=Kho Jabing hanged after bid to defer execution fails, lawyers receive ticking-off from court|url=https://www.todayonline.com/singapore/kho-jabing-hanged-after-bid-defer-execution-fails-lawyers-receive-ticking-court?cid=h3_referral_inarticlelinks_03092019_todayonline|website=Today Singapore|access-date=10 March 2021}}</ref><ref>{{Cite web|date=18 May 2016|url=https://theindependent.sg/un-calls-on-the-singapore-government-to-halt-the-execution-of-kho-jabing/|title=UN calls on the Singapore Government to halt the execution of Kho Jabing|website=The Independent|access-date=10 March 2021}}</ref><ref>{{Cite web|title=Amnesty urges Singapore to grant Malaysian man clemency|date=2015-11-06|url=https://www.asiaone.com/singapore/amnesty-urges-singapore-grant-malaysian-man-clemency|archive-url=https://web.archive.org/web/20171023133453/http://www.asiaone.com/singapore/amnesty-urges-singapore-grant-malaysian-man-clemency|url-status=dead|archive-date=October 23, 2017|website=AsiaOne|access-date=10 March 2021}}</ref>
*[[2019]] &ndash; The [[International System of Units]] (SI): The base units are redefined, making the [[International Prototype of the Kilogram|international prototype of the kilogram]] obsolete.
*[[2022]] &ndash; [[Russo-Ukrainian War]]: Russia claims full control of the Ukrainian city of [[Mariupol]] after a nearly [[Siege of Mariupol|three-month siege]].<ref>{{cite web|title=Russia claims to have taken full control of Mariupol|url=https://apnews.com/article/russia-ukraine-kyiv-prisoners-of-war-71d0dfb842caaaad30b92671637c1f3b|author1=Becatoros, Elena|author2=Oleksandr Stashevskyi|author3=Ciaran McQuillan|website=APNews.com|date=May 20, 2022|access-date=June 8, 2022}}</ref>