|Holiday name||Holiday location||Holiday type|
|Macau S.A.R. Establishment Day||Macau||Public Holiday|
|International Human Solidarity Day||-||International (Activity & Action, Awareness & Cause, United Nations)|
|Abolition of Slavery||Reunion||Public Holiday|
|National Sangria Day||-||Unofficial (Food & Drinks)|
|National Ugly Christmas Sweater Day||-||Unofficial (Fun & Joy, Weird & Obscure)|
|Underdog Day||-||Unofficial (Appreciation & Honor)|
|Mudd Day||-||Unofficial (Culture & History)|
|December Solstice||Multiple [Show]||Season|
|Games Day||-||Unofficial (Activity & Action, Fun & Joy)|
|Go Caroling Day||-||Unofficial (Art & Entertainment)|
Historical Events on December 20
- 1606: Three ships loaded with settlers and supplies is set sail by the Virginia Company. The purpose of these ships is to establish a colony at Jamestown, Virginia.
- 1803: Celebrated with a ceremony in New Orleans, the Louisiana Purchase is formally completed.
- 1860: South Carolina attempts to secede from the United States.
- 1915: The remaining Australian troops in Gallipoli are evacuated during World War I.
- 1916: After nine months of fighting, the French are victorious after the Battle of Verdun during World War I.
- 1924: Adolf Hitler is officially released from Landsberg Prison in Bavaria.
- 1942: The city of Calcutta, India are fiercely bombed by Imperial Japanese Air Forces.
- 1952: Almost 90 people are killed when a U.S Air Force C-124 crashes in Moses Lake, Washington in the USA.
- 1995: Peacekeeping operations in Bosnia are begun by NATO.
- 1995: Almost 160 people are killed when American Airlines Flight 965 crashes into a mountain 31 miles north of Cali, Columbia.
- 2004: On this day, one of the largest bank robberies in U.K history occurs when thieves steal £26.5 million of currency from Northern Bank in Belfast, Northern Ireland.
- 2007: Elizabeth II officially becomes the oldest monarch of the U.K. She surpassed even Queen Victoria who live for over 81 years and 7 months.
- 2007: Two paintings are stolen from the São Paulo Museum of Art on this day. “O Lavrador de Café” by Cândido Portinari and the “Portrait of Suzanne Bloch” by Pablo Picasso.
Famous Birthdays on December 20
- American businessman and founder of Firestone Tire Co., Harvey Samuel Firestone is born in 1868.
- American actor Charley Grapewin is born in 1869.
- American actress Mala Powers is born in 1931.
- American actor John Hillerman is born in 1932.
- American soul singer Kim Weston is born in 1939.
- American drummer Bobby Colomby is born in 1944.
- Israeli-English magician and illusionist, Uri Geller is born in 1946.