- China began massive economic reforms. (1978) Deng Xiaoping became the leader of the People's Republic of China on this day, and began a series of economic overhauls that pulled the country out of the poverty created by the Great Leap Forward. It was the beginning of China's astonishing economic growth in the late 20th century.
- The Brandenburg Gate in the Berlin Wall was opened for good. (1989) The gate had been one of the main Berlin Wall crossings, but it had been closed since 1961. Though the Berlin Wall had fallen about a month earlier, the formal opening of the Brandenburg gate was an official recognition of the end of hostilities between East and West Germany.
- The first American navy was commissioned. (1775) The Continental Congress, the governing body during the American Revolution, created the Continental Navy, the first American naval force. The first Admiral only went on one mission before he was relieved of command. He was instructed to assess and possibly attack the British in Chesapeake Bay. After he saw the British forces, he decided the fight would be unfeasible, and so set off for the Bahamas with the American fleet. Though he attacked and defeated a British port once he got to the Bahamas, he was relieved of command as soon as he got back to America.
- Russian author Fyodor Dostoevsky's execution was called off at the last minute. (1949) Dostoevsky had been imprisoned for allegedly taking part in anti-government activities. He received his reprieve while actually standing in front of the firing squad, and was sentenced to a Siberian labor camp instead.
- The first rural speed limits were posted in the UK. (1965) Before this day, there were no speed limits on non-city roads in the UK — speeds were left up to the driver's discretion. After several multi-car pileups and reports of cars regularly going in excess of 150 mph (240 kph), a maximum speed limit of 70 mph (112 kph) was set.
- Christmas lights were invented. (1882) Edward Johnson, a laboratory worker of Thomas Edison's, strung 80 red, white, and blue bulbs together to make the first string of Christmas lights. The idea didn't take off right away though — Christmas lights were expensive, and most people couldn't afford them until the early 20th century.
- The government of Romanian Dictator Nicolae Ceausescu was overthrown. (1989) Ceausescu had kept the country socially and economically stunted with extreme nationalism and a cult of personality. He and his wife fled the country when rioting broke out in most of the major cities in Romania. They were quickly caught, convicted of mass murder, and executed on December 25 of the same year.
- Beethoven's Fifth Symphony premiered in Vienna. (1808) The concert did not go very well, and Beethoven actually started it over in the middle because the orchestra played so poorly. The Fifth Symphony went on to become one of the most well-recognized pieces of classical music of all time.
- The first gorilla was born in captivity. (1956) Colo, the first gorilla born into captivity, came into the world at the Columbus Zoo in Ohio. Her birth was a turning point in zoos' animal care standards, since many zoos started focusing more on conservation and breeding animals for zoos rather than taking them out of the wild. Since Colo's birth, more than 30 gorillas have been born at the Columbus Zoo.
- The US Embargo Act of 1807 came into effect. (1807) The act prohibited any American ships from trading with foreign countries, which was extremely unpopular with merchants. Although it was created in an attempt to keep America out of France and Britain's ongoing conflict, it led to the British-American War of 1812.