December 1: Miguel Alemán Valdés takes office as President of Mexico.

December 2 The International Whaling Commission was signed in Washington to "provide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry".

December 7: A fire at the Winecoff Hotel in Atlanta, United States kills 119.

December 11: UNICEF (the United Nations Children's Emergency Fund) is founded.

December 12: The United Nations severs relations with Franco's Spain and recommends that member countries sever diplomatic relations. - Léon Blum founds a government of socialist parties in France. - Iranian troops recapture the Azerbaijan province and the Kurdish Republic of Mahabad, both of which had seceded earlier in the year.

December 14: The International Labour Organization becomes a specialized agency of the United Nations.

December 15: The first election to the Representative Assembly of French India was held.

December 16: Siam joins the United Nations (changes name to Thailand in 1949).

December 19: Viet Minh forces begin a war against French occupying forces in Vietnam, succeeding in 1954 with France's surrender at Dien Bien Phu.

December 20: Frank Capra's It's a Wonderful Life, featuring James Stewart, Donna Reed, Lionel Barrymore, Henry Travers, and Thomas Mitchell, is released in New York. - At least 1,362 people are killed in an earthquake and associated tsunami in Japan.

December 22: The Havana Conference begins between U.S. organized crime bosses in Havana, Cuba.

December 24: France's Fourth Republic is founded.

December 25: The first artificial, self-sustaining nuclear chain reaction in Europe was initiated within the Soviet (Russian) nuclear reactor F-1.

December 26: The Flamingo Hotel opens on the Las Vegas Strip. - David Lean's Great Expectations, based on the Charles Dickens novel, and featuring John Mills, Valerie Hobson, Martita Hunt, Alec Guinness, Francis L. Sullivan, Jean Simmons, and Finlay Currie, is released to great acclaim in the UK.

December 31: President Harry Truman delivers Proclamation 2714, which officially ends hostilities in World War II. (source: Wikipedia)