What happened on December 21 ?

69 - Year of the four emperors: Following Galba, Otho and Vitellius, Vespasian becomes the fourth Emperor of Rome within a year.

1620 - Plymouth Colony: William Bradford and the Mayflower Pilgrims land on what is now known as Plymouth Rock in Plymouth, Massachusetts.

1861 - Medal of Honor: Public Resolution 82, containing a provision for a Navy Medal of Valor, is signed into law by President Abraham Lincoln.

1872 - Challenger expedition: HMS Challenger, commanded by Captain George Nares, sails from Portsmouth.

1913 - Arthur Wynne's "word-cross", the first crossword puzzle, is published in the New York World.

1917 - Meiji Dairies, a Japanese dairy industry company, is founded.

1937 - The film Snow White and the Seven Dwarfs is premiered at the Carthay Circle Theater in Los Angeles.

1958 - French presidential election, 1958: Charles de Gaulle is elected President of France as his Union des Démocrates pour la République party gain 78.5% of the vote.

1962 - Rondane National Park is established as Norway's first national park.

1968 - Project Apollo: Apollo 8, crewed by Frank Borman, Jim Lovell and William Anders, is launched from the Kennedy Space Center in Florida.

1979 - Lancaster House Agreement: An independence agreement for Rhodesia is signed in London by Lord Carrington, Sir Ian Gilmour, Robert Mugabe, Joshua Nkomo, Bishop Abel Muzorewa and Dr S C Mundawarara.

1987 - The passenger ferry Doña Paz sinks after colliding with the oil tanker Vector 1 in the Tablas Strait in the Philippines, killing 1,565.

1988 - A bomb explodes on board Pan Am flight 103 over Lockerbie, Dumfries and Galloway, killing 270.

1999 - The Spanish Civil Guard intercepts a van loaded with 950 kg of explosives which ETA intend to use to blow up Torre Picasso in Madrid.

2012 - The Long Count of the Maya calendar recycles according to the most popular correlation. A minority argues it does so on December 23, 2012.