On Oct. 20, 1803, the U.S. Senate ratified the Louisiana Purchase.

In 1973, in what would become known as the “Saturday Night Massacre,” special Watergate prosecutor Archibald Cox was dismissed and Attorney General Elliot L. Richardson and Deputy Attorney General William B. Ruckelshaus resigned. Also, the Sydney Opera House was officially opened by Queen Elizabeth II.

In 1977, three members of the rock group Lynyrd Skynyrd, including the lead singer Ronnie Van Zant, were killed along with three others in the fatal crash of a chartered plane near McComb, Mississippi.

In 2011, Moammar Gadhafi, 69, Libya’s dictator for 42 years, was killed as revolutionary fighters overwhelmed his hometown of Sirte and captured the last major bastion of resistance two months after his regime fell.