Massive tsunami causes damage and kills thousands in India, Indonesia, Malaysia, Sri Lanka and Thailand. The tsunami was precipitated by a 9.1 magnitude earthquake off the coast of Sumatra, Indonesia. The earthquake was the third strongest earthquake ever measured using the Richter scale in recorded history. The other two were the Valdivia earthquake in Chile in 1960, with a magnitude of 9.5 and the Prince William Sound earthquake in Alaska in 1964, with a magnitude of 9.2. The Indian Ocean earthquake killed about 200,000 people and is considered one of the deadliest natural disasters in recent history.

The December issue of Times magazine proclaimed the personal computer as the "Man of the Year". The Man of the Year tradition began in 1927 at Time magazine as a way to identify and showcase those that influenced the year and its events significantly. In 1999, the feature was renamed Person of the Year.

First Kwanzaa celebrations. The week-long cultural holiday is celebrated among African diaspora in the United States and was created by Maulana Karenga, a professor of Africana Studies and a key figure in the Black Power movement. The holiday is celebrated annually from December 26 to January 1, and it is a recognition of African culture and heritage.

U.S. President Franklin D. Roosevelt signed the bill, making the fourth Thursday of November as Thanksgiving Day into federal law. The holiday has been celebrated officially in the United States since 1863. The first Thanksgiving is thought to have been observed by early settlers in the Massachusetts Bay Colony after their first harvest in 1621.

Nobel Prize winners Marie and Pierre Curie announce the existence of Radium. The radioactive element has an atomic number of 88 and is known by the symbol Ra. In its pure form, it is a highly toxic element and is not used extensively for scientific purposes.