2015 A landmark climate change agreement was reached at a UN conference in Paris as 195 countries agreed to limit greenhouse gas emissions; the accord effectively replaced the Kyoto Protocol.

New Zealand sighted
On this day in 1642, Dutch navigator Abel Tasman sighted South Island, New Zealand, and later, mistaking the strait north of the island for a bay, believed he had found the west coast of a hypothetical southern continent.

Roald Amundsen's arrival at the South Pole
One of the greatest figures in the history of polar exploration was Norwegian explorer Roald Amundsen, who left Norway for Antarctica in June 1910 and on this day in 1911 became the first person to reach the South Pole.

2011 The Iraq War officially ended as the United States formally declared that its mission in the country was over.

Boston Tea Party
On this day in 1773, in what is known as the Boston Tea Party, American colonists disguised as Mohawk Indians threw 342 chests of tea belonging to the British East India Company into Boston Harbor to protest a tax on tea.

Flight of the Wright brothers
On this day in 1903 near Kitty Hawk, North Carolina, brothers Orville and Wilbur Wright made the first successful sustained flights in an airplane—Orville first, gliding 120 feet (36.6 metres) through the air in 12 seconds

Slavery abolished in the United States
On this day in 1865, by proclamation of the U.S. secretary of state, the Thirteenth Amendment to the Constitution, outlawing slavery, officially entered into force, having been ratified by the requisite states on December 6.

1971 The sci-fi drama A Clockwork Orange, Stanley Kubrick's adaptation of a novel by Anthony Burgess, had its world premiere; although widely acclaimed, the movie's violent and sexually explicit scenes proved controversial, and it received an X rating when released in the United States.

Macau made an administrative region of China
On this day in 1999, 12 years after an agreement was reached between China and Portugal, several centuries of Portuguese rule ended in Macau when it became a special administrative region under Chinese sovereignty

Radium discovered by Marie and Pierre Curie
On this day in 1898, having recently discovered polonium, future Nobel Prize winners Marie and Pierre Curie discovered the radioactive chemical element radium, a silvery white metal that would be used to treat cancer.

1989 The Brandenburg Gate in Berlin was reopened, signifying the reunification of East and West Germany.

2013 Russian weapons designer Mikhail Kalashnikov—who invented the AK-47 (automatic Kalashnikov Model 1947), an assault rifle that became one of the most successful and ubiquitous firearms of the modern era—died in Izhevsk, Russia.

December 24, 1943
Gen. Eisenhower is named to command Allied armies slated to invade western Europe; Lt. Gen. Spaatz is appointed overall commander of U.S. strategic bombing air force operating against the reich; Gen. Montgomery is appointed to lead British troops under Eisenhower.

Christmas celebrated worldwide
Though the precise origin of the date is unclear, Christmas, commemorating the birth of Jesus Christ, is celebrated on this day, having been first identified as the date of Jesus' birth by Sextus Julius Africanus in 221.

Indian Ocean tsunami
On this day in 2004, a large earthquake shook the Indian Ocean floor west of the island of Sumatra, triggering a devastating tsunami that swamped coastal areas from Thailand to Africa and killed more than 200,000 people.