August 11

• August 11, 3114 BC
  The Mayan calendar, a system of calendars consisting of several counts of different lengths, begins in pre-Columbian Mesoamerica
• August 11, 117
  The Roman army of Syria hail its legate, Hadrian, as emperor, which made the senate's formal acceptance an almost meaningless event
• August 11, 991
  Danes under Olaf Tryggvason defeat Anglo-Saxons forces at Battle of Maldon and kill Ealdorman of Essex Byrhtnoth
• August 11, 1804
  Austrian Empire is proclaimed by Holy Roman Emperor Francis II, who assumes the title of the first Emperor of Austria, as a reaction to Napoleon making himself an emperor
• August 11, 1918
  Battle of Amiens, the opening phase of the Allied offensive against Germany, known as the Hundred Days Offensive, ends with Allied victory
• August 11, 1960
  Chad declares independence from France and becomes one of seventeen nations in Africa to gain independence in 1960, what became known as Year of Africa
• August 11, 1966
  Indonesia–Malaysia confrontation ends after Indonesian General Suharto sign peace agreement with Malaysia
• August 11, 1984
  United States President Ronald Reagan, during a voice check for a radio broadcast remarks "My fellow Americans, I'm pleased to tell you today that I've signed legislation that will outlaw Russia forever. We begin bombing in five minutes"
• August 11, 2003
  A heat wave in Paris causes temperatures up to 44 degrees C
• August 11, 2009
  The Perseid meteor showers peak at 200 observations per hour