Wikipedia:Selected anniversaries/December 20

This is a list of selected December 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, featured list 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.

← December 19	December 21 →

Staging area

Images

Use only ONE image at a time

• 
  Louisiana Purchase treaty
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  Donna Reed, James Stewart, and Karolyn Grimes in "It's a Wonderful Life"
• 
  Experimental Breeder Reactor I
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  Four light bulbs were lit with electricity generated from the EBR-1 reactor.
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  The sword-and-shield emblem of the Cheka-KGB
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  Flag of Concelho de Macau, one of the two concelhos of Macau under Portuguese rule
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  Luis Carrero Blanco
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  MV Doña Paz in port, 1984
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  City Hall, Cardiff

Ineligible

Blurb	Reason
Yaldā Night (Iran)	lots of CN tags (6)
1803 – As part of the Louisiana Purchase, New Orleans in the French territory of Louisiana was officially transferred to the United States.	refimprove section
1860 – South Carolina became the first of eleven slave states to declare secession from the U.S., leading to the eventual creation of the Confederate States of America and later the American Civil War.	citations needed and lead too long
1917 – The Cheka, the first Soviet secret police, was established by a decree issued by Vladimir Lenin.	lead too short, refimprove section
1941 – World War II: The Flying Tigers of the Chinese Air Force engaged in its first combat missions.	refimprove section
1946 – Frank Capra's popular Christmas film It's a Wonderful Life was first released in New York City.	refimprove section
1948 – Indonesian National Revolution: Dutch forces captured Yogyakarta, the Indonesian Republic's temporary capital, and seized President Sukarno.	unreferenced section and other issues
1951 – Experimental Breeder Reactor I near Arco, Idaho, U.S., became the world's first electricity-generating nuclear power plant when it became able to illuminate four 200-watt light bulbs.	expansion
1957 – The first flight of the Boeing 707, the first commercially successful jet airliner, took place.	refimprove section
1968 – The first two confirmed murders by the Zodiac Killer occurred in Benicia, California, in a case which remains unsolved.	Too much unreferenced
1973 – Luis Carrero Blanco, the prime minister of Spain, was assassinated by a bomb planted by members of the Basque nationalist and separatist group ETA.	Blanco: needs more footnotes; Assassination: refimprove
1989 – American forces invaded Panama to overthrow the government of Manuel Noriega.	refimprove section
2005 – U.S. district court Judge John E. Jones III ruled against mandating the teaching of "intelligent design" in his ruling on Kitzmiller v. Dover Area School District.	refimprove section

Eligible

• 1248 – Attempting to form an alliance with the Mongol Empire, Louis IX of France met with two of their envoys while en route to the Seventh Crusade.
• 1955 – Cardiff was recognised as the capital of Wales by the British government.
• 1984 – Twelve-year-old Jonelle Matthews disappeared from her home in Greeley, Colorado; her body was not discovered until 2019.
• 1987 – The deadliest peacetime maritime disaster in history occurred when the MV Doña Paz sank after colliding with an oil tanker in the Tablas Strait in the Philippines, resulting in an estimated 4,385 deaths.
• 1988 – The United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances, governing international cooperation against the illegal drug trade, opened for signatures.
• 1995 – American Airlines Flight 965 crashed into a mountain in Buga, Colombia, killing most of those on board.
• 2007 – Pablo Picasso's Portrait of Suzanne Bloch was stolen from the São Paulo Museum of Art before being recovered about three weeks later.
• Born/died this day: | Pope Zephyrinus |d|217| Richard Boyle, 2nd Viscount Shannon |d|1740| John Bell |d|1820| Dan Leno |b|1860| Kan'ichi Asakawa |b|1873| Evelyn Colon |d|1976| Beatrice Beeby |d|1991| Dawn Steel |d|1997

December 20

Russian and U.S. Implementation Force troops

• 1852 – Led by George Cathcart, British troops defeated Basuto and Taung forces at the Battle of Berea in present-day Lesotho, leading to an offer of peace from King Moshoeshoe I.
• 1940 – The superhero Captain America made his first published appearance in the comic book Captain America Comics #1.
• 1980 – NBC aired the American football match between the New York Jets and the Miami Dolphins without announcers.
• 1995 – Mandated by the Dayton Agreement that ended the Bosnian War, the NATO-led Implementation Force (troops pictured) began peacekeeping operations in Bosnia and Herzegovina.
• 1999 – Portugal transferred the sovereignty over Macau, which it had administered since the mid–16th century, to China.

• Ambroise Paré (d. 1590)
• Jean Jannon (d. 1658)
• Bill O'Reilly (b. 1905)
• Elizabeth Kekaʻaniau (d. 1928)

More anniversaries:

• December 19
• December 20
• December 21