1862: A Union Army captures New Orleans
1862: Rallies are held through the Country demanding an eight hour work day. These rallies ended in the Haymarket square affair.
1893: The World's Colombians Exposition opened in Chicago
1898: Battle of Manila Bay, Spanish American War, The US navy destroys the Spanish fleet in the first battle of the war.
1915: The RMS Lusitania departs from New York City on her two hundred and second, and final, crossing of the North Atlantic. Six days later, the ship is torpedoed off the coast of Ireland with the loss of 1,198 lives, including 128 Americans, rousing American sentiment against Germany.
1930: The dwarf planet Pluto is officially named.
1931: The Empire State Building is dedicated in New York City.
1945: A German newsreader officially announces that Adolf Hitler has "fallen at his command post in the Reich Chancellery fighting to the last breath against Bolshevism and for Germany".1948: The Democratic People's Republic of Korea (North Korea) is established, with Kim Il-sung as leader.
1956: The polio vaccine developed by Jonas Salk is made available to the public.
1960: Cold War: U-2 incident – Francis Gary Powers, in a Lockheed U-2 spy plane, is shot down over the Soviet Union, sparking a diplomatic crisis.
1971: Amtrak (the National Railroad Passenger Corporation) is formed to take over U.S. passenger rail service.
1991: Rickey Henderson of the Oakland Athletics steals his 939th base, making him the all-time leader in this category. However, his accomplishment is overshadowed later that evening by Nolan Ryan of the Texas Rangers, when he pitches his seventh career no-hitter, breaking his own record.
2003: In what becomes known as the "Mission Accomplished" speech, on board the USS Abraham Lincoln (off the coast of California), U.S. President George W. Bush declares that "major combat operations in Iraq have ended".
2011: United States President Barack Obama announces that U.S. forces have killed Al-Qaeda leader Osama bin Laden.
http://en.wikipedia.org/wiki/May_1