August 20th is the 232nd day of the year (233rd in leap years) in the Gregorian calendar. There are 133 days remaining until the end of the year.
636 – Rashidun forces led by Khalid ibn al-Walid took control of Syria and Palestine in the Battle of Yarmouk, marking the first great wave of Muslim conquests after the death of Muhammad.
1710 – War of the Spanish Succession: The Spanish-Bourbon army commanded by the Marquis de Bay was soundly defeated by a multinational army led by the Austrian commander Guido Starhemberg.
1909 – Pluto was photographed for the first time at the Yerkes Observatory in Williams Bay, Wisconsin, U.S., 15 years before it was officially discovered by Clyde Tombaugh.
1950 – Korean War: United Nations forces repelled an attempt by North Korea to capture the city of Taegu.
1988 – Fires in the United States’ Yellowstone National Park destroyed more than 150,000 acres (610 km2), the single-worst day of the conflagration.
Don King turns 87
Connie Chung turns 72
Joan Allen turns 62
David Walliams turns 46
Amy Adams turns 44
Andrew Garfield turns 35
Demi Lovato turns 26
Liana Liberato turns 23