December 6 is the 340th day of the year in the Gregorian calendar. There are 25 days remaining until the end of the year.
963 – Pope Leo VIII is appointed to the office of Protonotary and begins his papacy as antipope of Rome.
1060 – Béla I is crowned king of Hungary.
1240 – Mongol invasion of Rus': Kiev under Daniel of Galicia and Voivode Dmytro falls to the Mongols under Batu Khan.
1534 – The city of Quito in Ecuador is founded by Spanish settlers led by Sebastián de Belalcázar.
1648 – Colonel Thomas Pride of the New Model Army purges the Long Parliament of MPs sympathetic to King Charles I of England, in order for the King's trial to go ahead; came to be known as "Pride's Purge".
1704 – Battle of Chamkaur: During the Mughal-Sikh Wars, an outnumbered Sikh Khalsa defeats a Mughal army.
1745 – Charles Edward Stuart's army begins retreat during the second Jacobite Rising.
1790 – The U.S. Congress moves from New York City to Philadelphia.
1846 – American and Californio forces clash at the Battle of San Pasqual
1865 – Georgia ratifies 13th Amendment to the U.S. Constitution[1]
1877 – The first edition of The Washington Post is published.
1884 – The Washington Monument in Washington, D.C., is completed.
1897 – London becomes the world's first city to host licensed taxicabs.
1904 – Theodore Roosevelt articulated his "Corollary" to the Monroe Doctrine, stating that the U.S. would intervene in the Western Hemisphere should Latin American governments prove incapable or unstable.
1907 – A coal mine explosion at Monongah, West Virginia, kills 362 workers.
1912 – The Nefertiti Bust is discovered.
1916 – World War I: The Central Powers capture Bucharest.
1917 – Finland declares independence from Soviet Russia.
1917 – Halifax Explosion: A munitions explosion near Halifax, Nova Scotia kills more than 1,900 people in the largest artificial explosion up to that time.
1917 – World War I: USS Jacob Jones is the first American destroyer to be sunk by enemy action when it is torpedoed by German submarine SM U-53.
1921 – The Anglo-Irish Treaty is signed in London by British and Irish representatives.
1922 – One year to the day after the signing of the Anglo-Irish Treaty, the Irish Free State comes into existence.
1928 – The government of Colombia sends military forces to suppress a month-long strike by United Fruit Company workers, resulting in an unknown number of deaths.
1933 – U.S. federal judge John M. Woolsey rules that James Joyce's novel Ulysses is not obscene.
1941 – World War II: The United Kingdom and Canada declare war on Finland in support of the Soviet Union during the Continuation War. Camp X opens in Canada to begin training Allied Secret Agents for the War.
1947 – The Everglades National Park in Florida is dedicated.
1953 – Vladimir Nabokov completes his controversial novel Lolita.
1956 – A violent water polo match between Hungary and the USSR takes place during the 1956 Summer Olympics in Melbourne, against the backdrop of the Hungarian Revolution of 1956.
1957 – Project Vanguard: A launchpad explosion of Vanguard TV3 thwarts the first United States attempt to launch a satellite into Earth orbit.
1967 – Adrian Kantrowitz performs the first human heart transplant in the United States.
1969 – Altamont Free Concert: At a free concert performed by the Rolling Stones, eighteen-year old Meredith Hunter is stabbed to death by Hells Angels security guards.
1971 – Pakistan severs diplomatic relations with India, initiating the Indo-Pakistani War of 1971.
1973 – The Twenty-fifth Amendment: The United States House of Representatives votes 387–35 to confirm Gerald Ford as Vice President of the United States. (On November 27, the Senate confirmed him 92–3.)
1975 – The Troubles: Fleeing from the police, a Provisional IRA unit takes a British couple hostage in their flat on Balcombe Street, London, beginning a six-day siege.
1977 – South Africa grants independence to Bophuthatswana, although it is not recognized by any other country.
1978 – Spain ratifies the Spanish Constitution of 1978 in a referendum.
1982 – The Troubles: The Irish National Liberation Army bombs a pub frequented by British soldiers in Ballykelly, Northern Ireland, killing eleven soldiers and six civilians
1989 – The École Polytechnique massacre (or Montreal Massacre): Marc Lépine, an anti-feminist gunman, murders 14 young women at the École Polytechnique in Montreal.
1991 – Yugoslav Wars: In Croatia, forces of the Serb-dominated Yugoslav People's Army (JNA) bombard Dubrovnik after laying siege to the city for seven months.
1992 – The Babri Masjid in Ayodhya, India, is demolished, leading to widespread riots causing the death of over 1,500 people.
1997 – A Russian Antonov An-124 Ruslan cargo plane crashes into an apartment complex near Irkutsk, Siberia, killing 67.
1998 – in Venezuela, Hugo Chávez is victorious in presidential elections.
2005 – An Iranian Air Force C-130 military transport aircraft crashes into a ten-floor apartment building in a residential area of Tehran, killing all 84 on board and 44 more on the ground.
2006 – NASA reveals photographs taken by Mars Global Surveyor suggesting the presence of liquid water on Mars.
2015 – Venezuelan elections are held. For the first time in 17 years the United Socialist Party of Venezuela loses its majority in parliament.
2017 – Donald Trump's administration officially announces the recognition of Jerusalem as capital of Israel.
