August 20

• August 20, 1191
  Crusader King Richard I executes some 2,700 Muslim prisoners in Acre
• August 20, 1530
  Hayreddin Barbarossa, a Barbary pirate, unites Algeria and Tunisia as military states under the Ottoman caliphate and becomes admiral of the Ottoman fleet
• August 20, 1619
  The first African slaves arrive to North America aboard a Dutch privateer and dock in Jamestown, Virginia, with twenty human captives among its cargo
• August 20, 1672
  Johan de Witt, Grand Pensionary of Holland and key figure in Dutch politics, is assassinated by a carefully organized lynch mob by a shot in the neck, and his naked body is hanged and mutilated beside body of his brother Cornelis de Witt
• August 20, 1745
  Bonnie Prince Charlie occupies Blair Castle, Scotland
• August 20, 1847
  General Winfield Scott wins the Battle of Churubusco, only 8 kilometers away from Mexico City
• August 20, 1860
  Robert O'Hara Burke leads a group of 15 men, 27 camels and 23 horses out of Melbourne on an expedition to cross Australia
• August 20, 1913
  Adolphe Pégoud becomes the first pilot to parachute from an aircraft
• August 20, 1939
  Soviet forces under Lieutenant General Georgi Zhukov successfully counterattack Japanese invaders at Nomanhan in the Mongolian People's Republic on the border with Manchukuo
• August 20, 1940
  Ramón Mercader, agent of Josef Stalin, fatally stabs Leon Trotsky with an ice pick in Mexico City
• August 20, 1956
  The Calder Hall atomic power station begins operation in Cumberland, Great Britain, generating up to 90,000 kilowatts of power and manufacturing plutonium becoming the world's first power station to generate electricity on an industrial scale
• August 20, 2011
  In the Battle of Tripoli, Libyan rebels take control the nation's capital, effectively overthrowing the government of Muammar Gaddafi