Today in History, 4/30

711: The Islamic conquest of Spain gets underway as Moorish troops land at Gibraltar.
1006: Supernova SN 1006, the brightest supernova in recorded history, appears in the constellation Lupus.
1492: Spain gives Christopher Columbus his commission of exploration.
1789: George Washington takes the oath of office and is sworn in as the first elected president of the United States.
1803: The United States purchases the Louisiana Territory from France for a cool $15 million, more than doubling the size of the country overnight.1812: The territory of Orleans becomes the 18th US state under the name Louisiana.
1877: Alice B. Toklas, longtime companion of Gertrude Stein is born.1900: Casey Jones dies in a train wreck in Vaughan, MS while trying to make up time on the Cannonball Express.1908: Eve Arden is born. She was in tons of stuff, but I remember her as the principal of Rydell High in Grease.1923: Al Lewis is born. He played Grandpa on The Munsters and was a perennial candidate for Mayor of New York.1925: Johnny Horton is born. He did Sink the Bismark and a bunch of other great songs.

1926: Cloris Leachman is born.

1927: Douglas Fairbanks and Mary Pickford become the first celebrities to leave their footprints in the cement outside of Grauman's Chinese Theater in Hollywood.
1933: Willie Nelson is born.
1939: NBC begins regularly scheduled television broadcasts in New York with the broadcast of the opening ceremonies to the New York World's Fair. The means that FDR is the first president to appear on TV.
1943: Operation Mincemeat kicks off as the submarine HMS Seraph surfaces in the Mediterranean. Its mission: deposit a dead man with fake invasion plans and dressed as a British military intelligence officer. This worked even better than planned - after the documents were discovered as fake the Germans later disregarded genuine document finds. Right up there with the decoding of Enigma at Bletchly Park, it's one of the great spy stories of WWII. I recommend The Man Who Never Was by Ewen Montagu. The movie's good too.
1945: Adolf and Eva commit suicide.
1947: The Boulder Dam is officially renamed the Hoover Dam (again).1973: During the Watergate Scandal, Nixon announces the resignations of John Ehrlichman and H.R. Haldeman.
1975: The Vietnam War ends as Communist forces capture Saigon and South Vietnam unconditionally surrenders.
1993: The World Wide Web is born at Cern.
1995: Bill Clinton becomes the first US President to visit Northern Ireland.

Today in History elements mostly cribbed from The History Channel, Wikipedia, The New York Times, The Jewish World Review, The Writer's Almanac and anything else I can dig up.