Today:
1775: The Battles of Lexington and Concord took place, signaling the start of the American Revolutionary War.
1897: The first Boston Marathon was held, with 15 participants starting in Ashland, Massachusetts.
1943: The Warsaw Ghetto Uprising began as Jewish residents resisted the final liquidation of the ghetto by Nazi forces.
1943: Albert Hofmann experienced the first intentional LSD trip, an event later celebrated as Bicycle Day.
1956: Actress Grace Kelly married Prince Rainier III of Monaco in a civil ceremony.
1961: The Bay of Pigs invasion of Cuba ended in defeat for the U.S.-backed forces.
1971: Sierra Leone declared itself a republic, ending its status as a Commonwealth realm.
1975: India’s first satellite, Aryabhata, was launched into space from a Soviet cosmodrome.
1993: The 51-day siege of the Branch Davidian compound in Waco, Texas, ended with a fire that destroyed the complex.
1995: The Oklahoma City bombing occurred, causing significant destruction at the Alfred P. Murrah Federal Building.