1492: Christopher Columbus sets sail on his first voyage with three ships, Santa María, Pinta and Niña from Palos de la Frontera, Spain for the “Indies”

1596: David Fabricius discovers light variation of Mira (1st variable star)

1914: Germany invades Belgium and declares war on France, beginning World War I

1934: Adolf Hitler merges the offices of German Chancellor and President, declaring himself “Führer” (leader)

1972: US Senate ratifies the Anti-Ballistic Missile Treaty with the Soviet Union to limit the use of missile systems capable of defending against missile-delivered nuclear weapons

Source: Onthisday.com