August 18

• August 18, 1227
  Genghis Khan, a Mongol conqueror, dies, which triggers subsequent division of Mongol empire among his sons
• August 18, 1459
  City of Smederevo falls under the Turks after three-months siege completing the Ottoman conquest of Serbia
• August 18, 1588
  A storm strikes the remaining 60 ships of the Spanish Armada under the Duke Alonso Pérez de Guzmán after which only 11 are left. Many of the ships go to Ireland where most of the Spaniards are killed by the English
• August 18, 1759
  The French fleet is destroyed by the British under Admiral Edward Boscawen, at the battle of Lagos Bay in southern Portugal
• August 18, 1807
  Robert Stevenson begins work on the 35-meters Bell Rock lighthouse at the mouth of Scotland's Firth of Forth, the world's oldest surviving sea-washed lighthouse
• August 18, 1838
  United States Exploring Expedition, an exploring and surveying expedition of the Pacific Ocean and surrounding lands, led by Charles Wilkes, departs from Hampton Roads
• August 18, 1846
  General Stephen W. Kearny proclaims all of New Mexico a territory of the United States and declares himself the military governor of the New Mexico Territory shortly after Capture of Santa Fe
• August 18, 1851
  The Platine War for the hegemony over South America begins between the Argentine Confederation and Empire of Brazil and its alliance
• August 18, 1862
  Dakota War of 1862 begins in Minnesota four young Sioux murder five white settlers at Acton Township, Minnesota
• August 18, 1870
  Prussian forces defeat the French at the Battle of Gravelotte, the largest battle during the Franco–Prussian War
• August 18, 1920
  Nineteenth Amendment to the United States Constitution, giving women right to vote, is ratified
• August 18, 1920
  Serbian geophysicist and astronomer Milutin Milanković links Earth's periodic long-term climate changes with orbital eccentricity and full cycles of Earth's axis precession, later called Milankovitch cycles
• August 18, 1955
  First Sudanese Civil War begins between the northern part of Sudan and the southern Sudan region