364: Roman Emperor Valentinian I appoints his brother Flavius Valens co-emperor

1854: Great Britain and France declare war on Russia, expanding the Crimean War

1910: First seaplane takes off from water under its own power, piloted by Henri Fabre from the Étang de Berre lagoon at Martigues, France

1939: Spanish Civil War ends, Madrid falls to the Nationalists headed by Francisco Franco

1946: Cold War: The United States State Department releases the Acheson-Lilienthal Report, outlining a plan for the international control of nuclear power.

1979: A partial meltdown at Three Mile Island nuclear plant in the US results in the release of radioactive gas and iodine into the atmosphere but no deaths

Source: Onthisday.com