May 18 is the 138th day of the year in the Gregorian Calendar (139th in leap years). There are 227 days remaining.

  1. 1152 - Henry II marries Eleanor of Aquitaine.
  2. 1268 - The Principality of Antioch, a crusader state, falls to the Mamluk Sultan Baibars in the Battle of Antioch; Baibars' destruction of the city of Antioch was so great as to permanently negate the city's importance.
  3. 1498 - Vasco da Gama reaches the port of Calicut, India
  4. 1593 - Playwright Thomas Kyd's accusations of heresy lead to an arrest warrant for Christopher Marlowe.
  5. 1631 - In Dorchester, Massachusetts, John Winthrop takes the oath of office and becomes the first Governor of Massachusetts.
  6. 1652 - Rhode Island passes the first law in North America making slavery illegal.
  7. 1765 - Fire destroys a large part of Montreal, Quebec.
  8. 1783 - First United Empire Loyalists reach Parrtown, Saint John, New Brunswick, Canada after leaving the United States.
  9. 1803 - Napoleonic Wars: The United Kingdom revokes the Treaty of Amiens and declares war on France.
  10. 1804 - Napoleon Bonaparte is proclaimed Emperor of the French by the French Senate.
  11. 1811 - Las Piedras Battle first great military triumph of the liberating revolution of the Río de la Plata in Uruguay leaded by Jose Artigas.
  12. 1848 - Opening of the first German National Assembly (Nationalversammlung) in Frankfurt, Germany.
  13. 1863 - American Civil War: The Siege of Vicksburg begins, ending on July 4.
  14. 1869 - Surrender and dissolution of the Ezo Republic to Japan.
  15. 1869 - The Public Credit Act is passed by Ulysses S. Grant, one of his first actions as President of the United States. The Act endorsed the payment of the national debt after the American Civil War in gold currency instead of greenbacks.
  16. 1876 - Wyatt Earp starts work in Dodge City, Kansas under Marshal Larry Deger.
  17. 1896 - The United States Supreme Court rules in Plessy v. Ferguson that separate but equal is constitutional.
  18. 1896 - Khodynka Tragedy: a mass panic on Khodynka Field during the festivities of the coronation of Russian Tsar Nicholas II resulted in the deaths of 1389 people.
  19. 1897 - Dracula, a novel by Irish author Bram Stoker is published.
  20. 1900 - The United Kingdom proclaims a protectorate over Tonga.
  21. 1910 - The Earth passes through the tail of Comet Halley.
  22. 1917 - World War I: The Selective Service Act passes the U.S. Congress giving the President the power of conscription.
  23. 1926 - Evangelist Aimee Semple McPherson disappears while visiting a Venice, California, beach.
  24. 1927 - The Bath School Disaster: Forty-five people are killed by bombs planted by a disgruntled school-board member in Michigan.
  25. 1933 - New Deal: President Franklin Delano Roosevelt signs an act creating the Tennessee Valley Authority.
  26. 1944 - World War II: Battle of Monte Cassino - Germans evacuate Monte Cassino and Allied forces take the stronghold after a struggle that claimed 20,000 lives.
  27. 1944 - Deportation of Crimean Tatars by the Soviet Union government.
  28. 1944 - World War II: SS troops burn down six villages in the Brkini hills in south western Slovenia.
  29. 1948 - The First Legislative Yuan of the Republic of China officially convenes in Nanking.
  30. 1953 - Jackie Cochran becomes the first woman to break the sound barrier (she flew in a F-86 Sabrejet at an average speed of 652.337 miles per hour (1049.835 km/h) at Rogers Dry Lake, California).
  31. 1958 - An F-104 Starfighter sets a world speed record of 1,404.19 mph (2,259.82 km/h).
  32. 1959 - Launching of the National Liberation Committee of Côte d'Ivoire in Conakry, Guinea.
  33. 1969 - Apollo program: Apollo 10 launches.
  34. 1974 - Nuclear test: Under project Smiling Buddha, India successfully detonates its first nuclear weapon becoming the sixth nation to do so.
  35. 1974 - Completion of the Warsaw radio mast, the tallest construction ever built at the time. It later collapses on August 8, 1991.
  36. 1980 - 1980 Mount St. Helens eruption: Mount St. Helens erupts in Washington, killing 57 people and causing $3 billion in damage.
  37. 1980 - Gwangju Massacre: Students in Gwangju, South Korea begin demonstrations, calling for democratic reforms.
  38. 1980 - Peru: Terrorist group Shining Path attacked a voting poll in the town of Chuschi, Ayacucho starting their activities.
  39. 1983 - In Ireland, scene of remarkable pirate radio broadcasting during the decade, the Government launched a crackdown, with the leading Dublin pirate Radio Nova being put off the air.
  40. 1990 - In France, a modified TGV train achieves a new rail world speed record - 515.3km/h - superseding the previous record of 406.9km/h set by the German InterCityExperimental train
  41. 1991 - Helen Sharman from Sheffield becomes the first Briton to orbit in Space
  42. 1991 - 18th May, Chinese Natural Disaster, Flood affecting 210,232,227. [1]
  43. 1992 - The Archivist of the United States issues a proclamation to officially announce that the 27th Amendment to the U.S. Constitution has been ratified, despite more than 200 years for completion of the ratification process by the state legislatures.
  44. 1993 - KISS releases their third live album, Alive III in the United States.
  45. 1994 - Michael Jackson marries Lisa Marie Presley in the Dominican Republic.
  46. 1995 - Alain Juppé becomes Prime Minister of France.
  47. 1998 - United States v. Microsoft: The United States Department of Justice and 20 U.S. states file an antitrust case against Microsoft.
  48. 2004 - Randy Johnson throws the 17th perfect game in Major League Baseball history and became the oldest pitcher to throw a perfect game.
  49. 2006 - The post Loktantra Andolan government passes a landmark bill curtailing the power of the monarchy and making Nepal a secular country.