December 2: A Luftwaffe bombing raid on the harbour of Bari, Italy, sinks an American ship with a mustard gas stockpile, causing numerous fatalities (though the exact death toll is unresolved, as the bombing raid itself causes hundreds of deaths too).

December 3: In reprisal for an act of sabotage, the SS and Gestapo execute 100 Warsaw Tramway workers. - Edward R. Murrow delivers his classic "Orchestrated Hell" broadcast over CBS Radio, describing a Royal Air Force nighttime bombing raid on Berlin.

December 4: World War II: In Yugoslavia, resistance leader Marshal Josip Broz Tito proclaims a provisional democratic Yugoslav government in-exile. - The Great Depression officially ends in the United States: With unemployment figures falling fast due to WWII-related employment, U.S. President Franklin D. Roosevelt closes the Works Progress Administration

December 4: Bolivia declares war on Romania and Hungary.

December 7: Chiara Lubich starts the humanitarian Focolare Movement in Trento, northern Italy.

December 13: Massacre of Kalavryta: The occupying 117th Jäger Division (Wehrmacht) machine-gun all adult males from Kalavryta in Greece, subsequently burning the town.

December 20: A military coup is staged in Bolivia.

December 24: World War II: U.S. General Dwight D. Eisenhower becomes Supreme Allied Commander Europe.

December 30: Subhas Chandra Bose sets up a pro-Japanese Indian government at Port Blair, India.

December: Supreme Headquarters Allied Expeditionary Force is established in London by General Dwight D. Eisenhower. (source: Wikipedia)