24 December

563 – The Byzantine church Hagia Sophia in Constantinople is dedicated for the second time after being destroyed by earthquakes.
1294 – Pope Boniface VIII is elected Pope, replacing St. Celestine V, who had resigned.
1777 – Kiritimati, also called Christmas Island, is discovered by James Cook.
1814 – The Treaty of Ghent is signed ending the War of 1812.
1818 – The first performance of "Silent Night" takes place in the church of St. Nikolaus in Oberndorf, Austria.
1826 – The Eggnog Riot at the United States Military Academy begins that night, wrapping up the following morning.
1851 – Library of Congress burns.
1865 – The Ku Klux Klan is formed.
1871 – Aida opens in Cairo.
1906 – Radio: Reginald Fessenden transmits the first radio broadcast; consisting of a poetry reading, a violin solo, and a speech.
1911 – Lackawanna Cut-Off railway line opens in New Jersey and Pennsylvania.
1913 – The Italian Hall Disaster ("1913 Massacre") in Calumet, Michigan, results in the death of 73 Christmas party goers held by striking mine workers, including 59 children.
1914 – World War I: The "Christmas truce" begins.
1924 – Albania becomes a republic.
1929 – Assassination attempt on Argentine President Hipólito Yrigoyen.
1939 – World War II: Pope Pius XII makes a Christmas Eve appeal for peace.
1941 – World War II: Kuching is conquered by Japanese forces.
1942 – World War II: French monarchist, Fernand Bonnier de La Chapelle, assassinates Vichy French Admiral François Darlan in Algiers.
1943 – World War II: U.S. General Dwight D. Eisenhower becomes the Supreme Allied Commander.
1951 – Libya becomes independent from Italy. Idris I is proclaimed King of Libya.
1953 – Tangiwai disaster: A railway bridge is destroyed by a lahar at Tangiwai, in the Central North Island of New Zealand, sending a fully loaded passenger train into the Whangaehu River, and killing 153 people.
1955 – NORAD Tracks Santa for the first time in what will become an annual Christmas Eve tradition.
1964 – Vietnam War: Viet Cong operatives bomb the Brinks Hotel in Saigon to demonstrate they can strike an American installation in the heavily guarded capital.
1966 – A Canadair CL-44 chartered by the United States military crashes into a small village in South Vietnam, killing 129.
1968 – Apollo Program: The crew of Apollo 8 enters into orbit around the Moon, becoming the first humans to do so. They performed 10 lunar orbits and broadcast live TV pictures that became the famous Christmas Eve Broadcast, one of the most watched programs in history.
1972 Japan Airlines Flight 472, operated Douglas DC-8-53 landed at Juhu Aerodrome instead of Santacruz Airport in Bombay.
1973 – District of Columbia Home Rule Act is passed, allowing residents of Washington, D.C. to elect their own local government.
1974 – Cyclone Tracy devastates Darwin, Australia.
1979 – The first European Ariane rocket is launched.
1980 – Witnesses report the first of several sightings of unexplained lights near RAF Woodbridge, in Rendlesham Forest, Suffolk, England, an incident called "Britain's Roswell".
1997 – The Sid El-Antri massacre (or Sidi Lamri) in Algeria kills 50-100 people.
2000 – The Texas 7 hold up a sports store in Irving, Texas. Police officer Aubrey Hawkins is murdered during the robbery.
2003 – The Spanish police thwart an attempt by ETA to detonate 50 kg of explosives at 3:55 p.m. inside Madrid's busy Chamartín Station.
2005 – Chad–Sudan relations: Chad declares a state of war against Sudan following a December 18 attack on Adré, which left about 100 people dead.
2008 – Lord's Resistance Army, a Ugandan rebel group, begins a series of attacks on Democratic Republic of the Congo, massacring more than 400.

Holidays and observances

Christian Feast Day:
Adela and Irmina
Christmas Eve (Christianity) and its related observances:
Aðfangadagskvöld, the day when the 13th and the last Yule Lad arrives to towns. (Iceland)
Feast of the Seven Fishes (Italy)
Jul (Denmark, Norway and Sweden)
Nochebuena (Spain and Spanish-speaking countries)
The Declaration of Christmas Peace (Old Great Square of Turku, Finland's official Christmas City)