MORE EVENTS ON THIS DAY

2016: American first lady and actress Nancy Reagan—who was first lady during the 1981–89 administration of her husband, President Ronald Reagan, and was noted as his most trusted adviser and the most zealous protector of his reputation—died in Los Angeles. [Test your knowledge of the first ladies of the United States.]

1986: American painter Georgia O'Keeffe—whose well-known works included large-format paintings of natural forms, especially flowers and bones—died at age 98. [ Take our quiz about famous artists, painters, and architects.]

1981: Journalist Walter Cronkite, who was known as “the most trusted man in America,” signed off as the longtime anchor of the CBS Evening News .

1964: American boxer Cassius Clay took the name Muhammad Ali, which was given to him by his spiritual mentor, Elijah Muhammad, leader of the Nation of Islam. [ Watch a video about Ali's life and career.]

1869: At a meeting of the Russian Chemical Society, Russian chemist Dmitri Mendeleev presented the first periodic table. [Take our quiz about the periodic table.]

1834: Toronto, now the financial and commercial centre of Canada, was incorporated. [Test your knowledge of Canada.]