1844 - Several people were killed aboard the USS Princeton when a 12-inch gun exploded.
1893 - Edward G. Acheson showed his patent for Carborundum.
1900 - In South Africa, British troops relieved Ladysmith, which had been under siege since November 2, 1899.
1953 - In a Cambridge University laboratory, scientists James D. Watson and Francis H.C. Crick discovered the double-helix structure of DNA.
1956 - A patent was issued to Forrester for a computer memory core.
1986 - Swedish Prime Minister Olof Palme was assassinated in Stockholm.
1994 - NATO made its first military strike when U.S. F-16 fighters shot down four Bosnian Serb warplanes in violation of a no-fly zone over central Bosnia.
1998 - Serbian police began a campaign to wipe out "terrorist gangs" in the Yugoslav province of Kosovo.