A Soviet agent drove an ice axe into Leon Trotsky's skull at his fortified villa in Mexico City; he died the next day.

RAF and Luftwaffe fighters clashed in intense dogfights over Kent and London's approaches, part of the pivotal air campaign that determined the fate of a planned German invasion.

A dog named Robot led four teenage boys to a hidden hole near Montignac, France, revealing 17,000-year-old painted caves.

RAF fighters repelled the largest Luftwaffe daylight raid on London, a turning point so costly for Germany it abandoned invasion plans for Britain.

Germany, Italy, and Japan signed the Tripartite Pact in Berlin, formally establishing the Axis alliance and dividing the world into spheres of influence.

Franklin D. Roosevelt defeated Wendell Willkie to win an unprecedented third presidential term, as war raged in Europe and Americans debated intervention.

French prehistorian Henri Breuil began his first detailed scientific survey of the Lascaux cave paintings, months after four teenagers stumbled upon the 17,000-year-old Paleolithic gallery.

Edson Arantes do Nascimento, later known as Pelé, was born in Três Corações, Brazil, destined to become football's most transcendent star.