2015: David Letterman hosts his last "Late Show," ending a 22-year, 6028 episode run.
Also on this day:
1873: Levi Strauss and tailor Jacob Davis received a U.S. patent for men's work pants made with copper rivets.
1927: Charles Lindbergh takes off from Roosevelt Field on Long Island, N.Y., aboard the Spirit of St. Louis on his historic solo flight to France.
1932: Amelia Earhart takes off from Newfoundland to become the first woman to fly solo across the Atlantic.
1961: A white mob attacks a busload of Freedom Riders in Montgomery, Ala., prompting the federal government to send in U.S. marshals to restore order. The group had left Washington in two buses heading for Louisiana. Later one bus was burned in Anniston, Ala.
1993: An estimated 93 million people tune in for the final first-run episode of "Cheers" on NBC.
2008: Doctors at Massachusetts General Hospital in Boston say Sen. Edward Kennedy, D-Mass., had been diagnosed with a malignant brain tumor.
2014: A group of retired professional football players file suit against the NFL, accusing the league of cynically supplying them with powerful painkillers and other drugs that kept them in the game but led to serious complications later in life.