1710 – In the Battle of Helsingborg, 14,000 Danish invaders under Jørgen Rantzau are decisively defeated by an equally sized Swedish force under Magnus Stenbock. This is the last time Swedish and Danish troops meet on Swedish soil.
1827 – The Baltimore and Ohio Railroad is incorporated, becoming the first railroad in America offering commercial transportation of both people and freight.
1849 – Regular steamboat service from the west to the east coast of the United States begins with the arrival of the in San Francisco Bay, four months 22 days after leaving New York Harbor.
1885 – The American Telephone and Telegraph Company is incorporated in New York as the subsidiary of American Bell Telephone. (American Bell would later merge with its subsidiary.)
1948 – Christiansborg Cross-Roads shooting in the Gold Coast, when a British police officer opens fire on a march of ex-servicemen, killing three of them and sparking major riots in Accra.
1953 – James Watson and Francis Crick announce to friends that they have determined the chemical structure of DNA; the formal announcement takes place on April 25 following publication in April's Nature (pub. April 2).
1954 – The first color television sets using the NTSC standard are offered for sale to the general public.
1998 – First flight of RQ-4 Global Hawk, the first unmanned aerial vehicle certified to file its own flight plans and fly regularly in U.S. civilian airspace.