December 21 is the 355th day of the year (356th in leap years) in the Gregorian calendar. There are 10 days remaining until the end of the year.
1901 – 2000
- 1907 - The Chilean army commits a massacre of at least 2,000 workers striking saltpeter miners in Iquique.
- 1910 - An underground explosion at Hulton Bank Colliery in Westhoughton, England, kills 344 miners.
- 1913 – First crossword puzzle is published in the New York World paper, created by Arthur Wynne.
- 1914 – First feature-length silent movie comedy, Tillie's Punctured Romance, starring Marie Dressler, Mabel Normand and Charles Chaplin, is released
- 1919 – Municipal elections held in Senegal (First round, second round is held December 28). The multiracial lists of the Independent Socialist Republican Party (PRSI) wins in all four municipalities.
- 1923 – Nepal changes from British protectorate to independent state.
- 1933 – Newfoundland becomes a crown colony.
- 1934 - President of Bolivia Daniel Salamanca is overthrown in a military coup.
- 1937 – First screening of Snow White and the Seven Dwarfs, the first feature-length animated movie.
- 1941 - A treaty of alliance is signed by Japan and Thailand.
- 1942 - Hundreds of workers striking for better pay and conditions at a tin mine in Bolivia are massacred.
- 1946 - The Nankaido earthquake in Japan kills over 1,300 people.
- 1958 – Charles de Gaulle is elected as the first President and establishes the Fifth Republic.
- 1962 – Rondane National Park, the first national park in Norway, is established.
- 1965 - The UN adopts the Declaration on the Elimination of All Forms of Racial Discrimination.
- 1967 - Louis Washkansky, who received the first successful heart transplant in Cape Town on December 3, dies 18 days after the operation.
- 1968 – Apollo 8 is launched.
- 1969 - The UN adopts the International Convention on the Elimination of All Forms of Racial Discrimination.
- 1978 - John Wayne Gacy is arrested for the killings of 33 boys and young men.
- 1979 – The United States government bails out the Chrysler Corporation
- 1979 – The Lancaster House Agreement was signed, effectively ending the white rule in Rhodesia under Ian Smith.
- 1984 - The Soviet Vega 2 probe is launched to the planet Venus.
- 1987 – The passenger ferry Doña Paz sinks after colliding with the oil tanker Vector 1 in the Philippines.
- 1988 – A terrorist bomb explodes and crashes Pan Am flight 103 a Boeing 747, over Lockerbie, Scotland killing 270, including 11 on the ground.
- 1991 - The former Soviet Union countries Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Moldova, Tajikistan and Turkmenistan join the Commonwealth of Independent States.
- 1994 – The Popocatepetl volcano in Mexico erupts.
- 1995 – Bethlehem goes from Israeli to Palestinian control.
- 1999 – Chadrika Kumaratunga is confirmed as Sri Lanka's Head of State.
- 1999 – The Spanish Civil Guard intercepts a van loaded with 950 kg of explosives intended by ETA to blow down Torre Picasso.
From 2001
- 2001 – Japanese television performer Masashi Tashiro got No. 1 temporarily in the Internet vote of Time's Person of the Year.
- 2002 – Vancouver, British Columbia city council declares "D.O.A. Day" in observance of the Canadian punk band D.O.A.'s decades of influence and accomplishments.
- 2005 - The United Kingdom introduces Civil Partnership for same-sex couples. Elton John and his partner David Furnish are among those who make use of this law on its first day.
- 2006 – Turkmenistan's President Saparmurat Niyazov dies.
- 2007 – Estonia, Latvia, Lithuania, Malta, Poland, Slovakia, Slovenia, the Czech Republic and Hungary implement the Schengen Agreement.
- 2010 – A partial lunar eclipse occurs on the day of the December solstice.
- 2012 – The Long Count of the Maya calendar resets itself according to the most popular correlation. A minority argues that it does so on December 23, 2012. This has been central to various predictions about December 21, 2012, ranging from spiritual and transformative to apocalyptic.
- 2012 - Having been posted on YouTube in July, and becoming a worldwide hit, the video of PSY's Gangnam Style reaches the milestone of a billion views on the video-sharing website.
- 2014 - Klaus Iohannis becomes President of Romania.
- 2014 - Beji Caid Essebsi is elected President of Tunisia.
- 2015 - Sepp Blatter and Michel Platini are banned from football for 8 years over corruption at FIFA.
- 2017 - Catalonia holds regional elections, with the coalition of parties supporting Catalan independence keeping its majority.
- 2017 - Birmingham, England, is given the right to host the 2022 Commonwealth Games.
Up to 1900
- 1118 – Thomas Becket, Archbishop of Canterbury (d. 1170)
- 1401 - Tommaso Masaccio, Italian painter (d. 1428)
- 1596 - Peter Mogila, Moldovan religious figure (d. 1646)
- 1603 - Roger Williams, English theologian (d. 1684)
- 1639 - Jean Racine, French writer (d. 1699)
- 1728 - Hermann Raupach, German composer (d. 1778)
- 1773 - Robert Brown, Scottish botanist (d. 1858)
- 1778 - Anders Sandoe Orsted, 3rd Prime Minister of Denmark (d. 1860)
- 1795 - Jack Russell, English dog breeder (d. 1883)
- 1795 – Leopold von Ranke, German historian (d. 1886)
- 1804 – Benjamin Disraeli, 1st Earl of Beaconsfield, Prime Minister of the United Kingdom (d. 1881)
- 1805 – Thomas Graham, Scottish chemist (d. 1869)
- 1811 – Archibald Campbell Tait, Archbishop of Canterbury (d. 1882)
- 1815 - Thomas Couture, French painter and educator (d. 1879)
- 1818 – Amalia of Oldenburg, Queen of Greece (d. 1875)
- 1823 - Jean-Henri Fabre, French entomologist, writer and poet (d. 1915)
- 1832 - John H. Ketcham, American general and politician (d. 1906)
- 1840 – Namik Kemal, Turkish nationalist poet (d. 1888)
- 1843 - Thomas Bracken, Irish-New Zealand poet (d. 1898)
- 1847 - John Chard, British military officer (d. 1897)
- 1850 – Zdenek Fibich, Bohemian composer (d. 1900)
- 1851 - Thomas Chipman McRae, 26th Governor of Arkansas (d. 1929)
- 1857 - Joseph Carruthers, Australian politician, 16th Premier of New South Wales (d. 1932)
- 1859 - Gustave Kahn, French poet (d. 1936)
- 1872 – Don Lorenzo Perosi, Italian composer (d. 1956)
- 1872 - Sidney Ainsworth, British actor (d. 1922)
- 1874 - Juan Bautista Sacasa, President of Nicaragua (d. 1946)
- 1874 - Josep Maria Sert, Catalan painter (d. 1945)
- 1876 - Jack Lang, 23rd Premier of New South Wales (d. 1975)
- 1877 - Jaan Sarv, Estonian mathematician and scholar (d. 1954)
- 1878 - Jan Łukasiewicz, Polish philosopher and mathematician (d. 1956)
- 1879 – Joseph Stalin, Soviet leader (d. 1953)
- 1885 - Frank Patrick, Canadian ice hockey player (d. 1960)
- 1888 - Jean Boulin, French long-distance runner (d. 1914)
- 1890 – H. J. Muller, American geneticist (d. 1967)
- 1891 - John William McCormack, American politician (d. 1980)
- 1892 – Walter Hagen, American golfer (d. 1969)
- 1892 – Rebecca West, British writer (d. 1983)
- 1896 – Leroy Robertson, American composer (d. 1971)
1901 – 1950
- 1902 – Ulrich Wilhelm Graf Schwerin von Schwanenfeld, German Resistance activist (d. 1944)
- 1905 – Anthony Powell, British writer (d. 2000)
- 1909 – Seicho Matsumoto, Japanese writer and journalist (d. 1992)
- 1913 – Arnold Friberg, American illustrator and painter (d. 2010)
- 1914 – Frank Fenner, Australian scientist (d. 2010)
- 1915 – Werner von Trapp, Austrian singer (d. 2007)
- 1917 – Heinrich Böll, German writer (d. 1982)
- 1918 – Kurt Waldheim, Austrian politician (d. 2007)
- 1918 – Donald Regan, American politician (d. 2003)
- 1920 – Alicia Alonso, Cuban ballerina; d. Twenty-nineteen
- 1924 – Rita Reys, Dutch jazz singer (d. 2013)
- 1925 – Olga Aroseva, Russian actress (d. 2013)
- 1926 – Arnost Lustig, Czech writer (d. 2011)
- 1926 – Joe Paterno, American football coach (d. 2012)
- 1927 – Takashi Hiraoka, Japanese mayor and journalist
- 1928 – Ed Nelson, American actor (d. 2014)
- 1930 – Kalevi Sorsa, Prime Minister of Finland (d. 2004)
- 1931 – Moira Orfei, Italian actress (d. 2015)
- 1932 – U. R. Ananthamurthy, Indian writer (d. 2014)
- 1933 – Robert Worcester, American businessman
- 1934 – Hanif Mohammad, Pakistani cricketer (d. 2016)
- 1934 – Giuseppina Leone, Italian sprinter
- 1935 – John G. Avildsen, American movie director and producer (d. 2017)
- 1935 – Yusuf Bey, American activist (d. 2003)
- 1935 – Edward Schreyer, Canadian politician
- 1935 – Lorenzo Bandini, Italian racing driver (d. 1967)
- 1936 – Hershel W. Gober, American politician
- 1937 – Jane Fonda, American actress
- 1938 – Frank Moorhouse, Australian author
- 1939 – Lloyd Axworthy, Canadian politician
- 1940 – Frank Zappa, American musician (d. 1993)
- 1942 – Hu Jintao, Chinese politician, former General Secretary of the Communist Party of China
- 1942 – Reinhard Mey, German singer-songwriter
- 1942 – Crispin Wright, British philosopher
- 1942 – Carla Thomas, American singer
- 1943 – Masafumi Hara, Japanese footballer
- 1943 – Albert Lee, English guitarist
- 1943 – Jack Nance, American actor (d. 1996)
- 1943 – Walter Spanghero, French rugby player
- 1944 – Bill Atkinson, English footballer
- 1944 – Michael Tilson Thomas, American conductor, pianist and composer
- 1945 – Doug Walters, English cricketer
- 1946 – Carl Wilson, American musician (The Beach Boys) (d. 1998)
- 1947 – Paco de Lucía, Spanish flamenco guitarist, songwriter and producer (d. 2014)
- 1948 – Samuel L. Jackson, American actor
- 1949 – Thomas Sankara, President of Burkina Faso (d. 1987)
- 1950 – Jeffrey Katzenberg, American movie producer
1951 – 1975
- 1953 - Betty Wright, American soul singer
- 1953 - András Schiff, Hungarian-British pianist and conductor
- 1954 – Chris Evert, American tennis player
- 1955 - Kazuyuki Sekiguchi, Japanese singer-songwriter and bass player
- 1955 – Jane Kaczmarek, American actress
- 1957 – Ray Romano, Italian-American comedian
- 1958 - Tamara Bykova, Russian athlete
- 1959 – Florence Griffith-Joyner, American athlete (d. 1998)
- 1959 - Michael Spindelegger, Austrian politician
- 1960 - Sherry Rehman, Pakistani journalist, politician and diplomat
- 1961 – Ryuji Sasai, Japanese video game designer
- '62 - Steven Mnuchin, 77th United States Secretary of the Treasury
- 1963 - Govinda, Indian actor and politician
- 1965 – Cem Oezdemir, German politician
- 1965 – Anke Engelke, German comedienne
- 1965 - Andy Dick, American comedian, actor, musician and television producer
- 1966 – Kiefer Sutherland, Canadian actor
- 1966 - Karri Turner, American actress
- 1966 - William Ruto, Kenyan politician
- 1967 – Mikheil Saakashvili, former President of Georgia
- 1969 - Julie Delpy, French-American model, actress, director and screenwriter
- 1969 - Jack Noseworthy, American actor
- 1969 - Mihails Zemlinskis, Latvian footballer
- 1970 - Jamie Theakston, English television presenter
- 1970 - Stefan Lövgren, Swedish handball player
- 1972 - Claudia Poll, Costa Rican swimmer
- 1972 - Gloria De Piero, English politician
- 1972 - Kirsten Oswald, Scottish politician
- 1972 - Y. S. Jaganmohan Reddy, Indian politician
- 1973 - Irakli Alasania, Georgian colonel and politician
- 1974 - Karrie Webb, Australian golfer
- 1975 - Charles Michel, President of the European Council and former Prime Minister of Belgium
From 1976
- 1976 – Lukas Rossi, Canadian rock singer
- 1977 - Emmanuel Macron, President of France
- 1978 - Alexander Wolf, German biathlete
- 1979 - Tuva Novotny, Swedish actress, singer and director
- 1979 - Steve Montador, Canadian ice hockey player (d. 2015)
- 1980 – Stefan Liv, Polish-born Swedish ice hockey player (d. 2011)
- 1981 – Cristian Zaccardo, Italian footballer
- 1982 - Charlie Cox, English actor
- 1982 – Mike Gansey, American basketball player
- 1982 – Iljo Keisse, Belgian cyclist
- 1983 - Steven Yeun, Korean-American actor
- 1984 – Darren Potter, Irish footballer
- 1985 – Tom Sturridge, British actor
- 1985 - Andrea Jeremiah, Indian actress and singer
- 1987 – Brad Howard, Australian footballer
- 1988 - Perri Shakes-Drayton, British athlete
- 1988 - Yasmin, British singer
- 1989 - Tamannaah, Indian actress
- 1990 - Alexa Goddard, British singer
- 1991 - Riccardo Saponara, Italian footballer
- 1995 - Bobby, South Korean rapper and composer
- 1996 - Kaitlyn Dever, American actress
Up to 1950
- 72 – Thomas the Apostle
- 882 - Hincmar, French archbishop (b. 806)
- 1295 – Marguerite Berenger of Provence, queen of Louis IX of France (b. 1221)
- 1308 – Henry I of Hesse (born 1244)
- 1375 – Giovanni Boccaccio, Italian writer (born 1313)
- 1504 – Bertold von Henneberg-Römhild, German archbishop and elector (born 1442)
- 1549 – Marguerite of Navarre, queen of Henry II of Navarre (born 1492)
- 1579 – Vicente Masip, Spanish painter (b. 1500)
- 1597 – Petrus Canisius, Dutch Jesuit (born 1521)
- 1737 - Alessandro Galilei, Italian architect (born 1691)
- 1807 – John Newton, English cleric and hymnist (born 1725)
- 1839 - Andrew Dung-Lac, Vietnamese martyr (born 1795)
- 1873 – Francis Garnier, French explorer (born 1839)
- 1882 - Francesco Hayez, Italian painter (born 1791)
- 1900 - Roger Wolcott, Governor of Massachusetts (b. 1847)
- 1907 - Klara Hitler, mother of Adolf Hitler (b. 1860)
- 1920 – Mohammed Abdullah Hassan, Somali nationalist leader (b. 1856)
- 1933 – Knud Rasmussen, Greenlandic explorer and anthropologist (b. 1879)
- 1935 – Kurt Tucholsky, German journalist and satirist (born 1890)
- 1937 – Frank B. Kellogg, 45th United States Secretary of State, recipient of the Nobel Peace Prize (born 1856)
- 1940 – F. Scott Fitzgerald, American writer (born 1896)
- 1945 – George S. Patton, American general (born 1885)
1951 – 2015
- 1955 - Garegin Njdeh, Armenian statesman (b. 1886)
- 1957 – Eric Coates, English composer (born 1886)
- 1958 – Lion Feuchtwanger, German writer (born 1884)
- 1964 – Carl Van Vechten, American writer and photographer (b. 1880)
- 1967 - Louis Washkansky, heart transplant patient (b. 1913)
- 1968 – Vittorio Pozzo, Italian FIFA World Cup-winning football manager (b. 1886)
- 1982 - Hafeez Jullundhri, Pakistani writer, poet and composer (b. 1900)
- 1983 - Paul de Man, Belgian critic (b. 1919)
- 1987 - John Spence, American musician (b. 1969)
- 1988 – Nikolaas Tinbergen, Dutch ornithologist, recipient of the Nobel Prize in Physiology or Medicine (born 1907)
- 1989 - Rotimi Fani-Koyode, Nigerian-English photographer (b. 1955)
- 1990 - Clarence Johnson, American engineer (b. 1910)
- 1992 – Albert King, American musician (born 1924)
- 1992 – Nathan Milstein, Ukrainian violinist (born 1903)
- 2001 – Dick Schaap, American sports journalist (born 1931)
- 2004 – Autar Singh Paintal, Indian medical scientist (born 1925)
- 2006 – Saparmurat Niyazov, President of Turkmenistan (b. 1940)
- 2008 - Dale Wasserman, American writer (b. 1914)
- 2009 – Edwin G. Krebs, American biochemist (b. 1918)
- 2010 – Enzo Bearzot, Italian footballer and FIFA World Cup-winning manager (b. 1927)
- 2012 - Lee Dorman, American musician (b. 1942)
- 2013 - David Coleman, British broadcaster (b. 1926)
- 2013 - Edgar Bronfman, Sr., Canadian-American businessman (b. 1929)
- 2013 - John Eisenhower, American general, historian and diplomat (b. 1922)
- 2014 - Horacio Ferrer, Uruguayan writer and poet (b. 1933)
- 2014 - Udo Jürgens, Austrian singer (b. 1934)
- 2014 - Sitor Situmorang, Indonesian poet and writer (b. 1923)
- 2014 - Billie Whitelaw, English actress (b. 1932)
- 2014 - Alan Williams, Welsh politician (b. 1930)
- 2014 - Morteza Ahmadi, Iranian actor (b. 1924)
- 2014 - Jane Bown, British photographer (b. 1925)
- 2014 - Frank Truitt, American basketball coach (b. 1925)
- 2015 - Carol Burns, Australian actress (b. 1947)
From 2016
- 2017 - Manouchehr Boroumand, Iranian weightlifter (b. 1934)
- 2017 - Ken Catchpole, Australian rugby player (b. 1939)
- 2017 - Dick Enberg, American sports broadcaster (b. 1935)
- 2017 - March Fong Eu, American politician; b. '22
- 2017 - Halvard Kausland, Norwegian jazz guitarist (b. 1945)
- 2017 - Jean-Pierre Lehmann, American-born Swiss economist; b. '45
- 2017 - Bruce McCandless II, American astronaut (b. 1937)
- 2017 - Francelino Pereira, Brazilian politician (b. 1921)
- 2017 - June Rowlands, Canadian politician, 60th Mayor of Toronto (b. 1924)
- 2017 - Roswell Rudd, American jazz trombonist (b. 1935)
- 2017 - John Vear, New Zealand cricketer (b. 1938)
- 2017 - Jerry Yellin, American World War II fighter pilot (b. 1924)
- 2018 - Gerard Bernacki, Polish priest; b. '42
- 2018 - Lars Hindmar, Swedish racewalker; b. '21
- Twenty-nineteen