- The Madrid Codices were discovered. (1967) The codices were personal notebooks of Leonardo da Vinci, and included almost 200 pages of drawings and notes. They were discovered in the National Library of Spain, where they had been misplaced for centuries.
- The cinematograph was patented. (1894) Two French brothers Auguste and Louis Lumière patented the machine, which was a combination of a movie camera and a projector. They recorded the first footage with it six days later, a short film of workers leaving their factory, which was the first film anyone ever paid to see.
- Astronomers announced the discovery of the largest "diamond" in the universe. (2004) The diamond was actually a white dwarf star which was found to be very similar in composition to a diamond. It was nicknamed "Lucy" after the Beatles' hit "Lucy in the Sky with Diamonds."
- The Battle of Chipyong-ni started. (1951) Known as the "Gettysburg of the Korean War," the battle was a major turning point for UN forces. It was the furthest the Chinese forces got into South Korea, and represented the beginning of their decline in the war.
- La Citoyenne, an early feminist newspaper, was founded. (1881) The newspaper strongly advocated changes in French law to enfranchise women, and was one of the first influential feminist publications in the Western world.
- ASCAP was founded. (1912) The American Society of Composers, Authors and Publishers was founded to protect the rights to their members' publications. Both John Philip Sousa and Irving Berlin were original ASCAP members.
- Galileo arrived in Rome for his trial. (1633) The famous astronomer, philosopher, and mathematician was accused of heresy for believing that the Earth revolves around the Sun. He was sentenced to indefinite house arrest, and stayed in his home until he died about ten years later.
- The League of Nations accepted Switzerland's neutrality. (1920) Switzerland had not been in a state of war since 1815, and had only rarely participated in wars before that. The nation insisted on the League of Nations recognizing its neutrality before it would agree to join.
- William and Mary became the monarchs of England. (1689) The two came to power after the bloodless Glorious Revolution, and enacted a number of policies that favored the rights of the people and Parliament, rather than the monarchy. They also enacted laws on the basis of political and personal rights, a new concept at the time.
- Thomas Edison observed the Edison Effect (1880) The Edison Effect, also known as thermionic emission, occurs when an object is induced to change its charge due to heat. The effect was originally discovered some seven years earlier in Britain, but was rediscovered by Thomas Edison on this day while he was trying to figure out why his light bulbs kept breaking.