451-Battle of the Catalaunian Plains: Roman and Visigoths forces defeat Attila the Hun in north east France, halting Hun invasion of Roman Gaul (exact date disputed)
1789-French Revolution: The Third Estate of the French Estates-General swears the Tennis Court Oath at the Palace of Versailles, swearing not to disband until a new constitution is formed
1840-American inventor Samuel Morse patents his telegraph
1895-First female PhD from an American University, earned by Caroline Willard Baldwin (in Science) at Cornell University
2020-Highest-ever temperature recorded in the Arctic circle, 38C (100F) in Verkhoyansk, Siberia