Martin Luther posted the 95 Theses on the door of the Wittenberg Palace church, marking the start of the Protestant Reformation in Germany.
Nevada became the 36th state.
Work on the Mount Rushmore monument was completed.
Rear Admiral G. J. Dufek became the first person to land an airplane at the South Pole.
Indian prime minister Indira Gandhi was assassinated.
Pope John Paul II admitted that the Roman Catholic Church had erred in convicting Galileo of heresy 350 years earlier.