| 86281 | July 31 | Event | 1938 – Bulgaria signs a non-aggression pact with Greece and other states of Balkan Antanti (Turkey, Romania, Yugoslavia). |
| 86282 | July 31 | Event | 1938 – Archaeologists discover engraved gold and silver plates from King Darius the Great in Persepolis. |
| 86283 | July 31 | Event | 1941 – The Holocaust: Under instructions from Adolf Hitler, Nazi official Hermann Göring, orders SS General Reinhard Heydrich to "submit to me as soon as possible a general plan of the administrative material and financial measures necessary for carrying |
| 86284 | July 31 | Event | 1945 – Pierre Laval, the fugitive former leader of Vichy France, surrenders to Allied soldiers in Austria. |
| 86285 | July 31 | Event | 1948 – At Idlewild Field in New York, New York International Airport (later renamed John F. Kennedy International Airport) is dedicated. |
| 86286 | July 31 | Event | 1948 – USS Nevada is sunk by an aerial torpedo after surviving hits from two atomic bombs (as part of post-war tests) and being used for target practice by three other ships. |
| 86287 | July 31 | Event | 1950 – United Nations Security Council Resolution 85 relating to Korean War is adopted. |
| 86288 | July 31 | Event | 1954 – First ascent of K2, by an Italian expedition led by Ardito Desio. |
| 86289 | July 31 | Event | 1961 – At Fenway Park in Boston, Massachusetts, the first All-Star Game tie in Major League Baseball history occurs when the game is stopped in the ninth inning because of rain. |
| 86290 | July 31 | Event | 1964 – Ranger program: Ranger 7 sends back the first close-up photographs of the moon, with images 1,000 times clearer than anything ever seen from earth-bound telescopes. |
| 86291 | July 31 | Event | 1970 – Black Tot Day: The last day of the officially sanctioned rum ration in the Royal Navy. |
| 86292 | July 31 | Event | 1971 – Apollo program: Apollo 15 astronauts become the first to ride in a lunar rover. |
| 86293 | July 31 | Event | 1972 – The Troubles: In Operation Motorman, the British Army re-takes the urban no-go areas of Northern Ireland. It is the biggest British military operation since the Suez Crisis of 1956, and the biggest in Ireland since the Irish War of Independence. La |
| 86294 | July 31 | Event | 1973 – A Delta Air Lines jetliner, flight DL 723 crashes while landing in fog at Logan International Airport, Boston, Massachusetts killing 89. |
| 86295 | July 31 | Event | 1975 – The Troubles: three members of a popular cabaret band and two gunmen are killed during a botched paramilitary attack in Northern Ireland. |
| 86296 | July 31 | Event | 1988 – Thirty-two people are killed and 1,674 injured when a bridge at the Sultan Abdul Halim ferry terminal collapses in Butterworth, Penang, Malaysia. |
| 86297 | July 31 | Event | 1991 – The United States and Soviet Union both sign the START I Strategic Arms Reduction Treaty, the first to reduce (with verification) both countries' stockpiles. |
| 86298 | July 31 | Event | 1992 – Georgia joins the United Nations. |
| 86299 | July 31 | Event | 1992 – Thai Airways International Flight 311 crashes into a mountain north of Kathmandu, Nepal killing all 113 people on board. |
| 86300 | July 31 | Event | 1999 – Discovery Program: Lunar Prospector: NASA intentionally crashes the spacecraft into the Moon, thus ending its mission to detect frozen water on the moon's surface. |
| 86301 | July 31 | Event | 2006 – Fidel Castro hands over power to brother Raúl Castro. |
| 86302 | July 31 | Event | 2007 – Operation Banner, the presence of the British Army in Northern Ireland, and the longest-running British Army operation ever, comes to an end. |
| 86303 | July 31 | Event | 2009 – Three members of the popular South Korean group TVXQ, (Kim Jae-joong, Kim Junsu, and Park Yoo-chun), filed lawsuit against their Korean management S.M. Entertainment. |
| 86304 | July 31 | Event | 2012 – Michael Phelps breaks the record set in 1964 by Larisa Latynina for the most medals won at the Olympics. |
| 86305 | July 31 | Event | 2014 – Gas explosions in the southern Taiwanese city of Kaohsiung kill at least 20 people and injure more than 270. |
| 86306 | July 31 | Birth | 1143 – Emperor Nijō of Japan (d. 1165) |
| 86307 | July 31 | Birth | 1396 – Philip the Good, French son of John the Fearless (d. 1467) |
| 86308 | July 31 | Birth | 1527 – Maximilian II, Holy Roman Emperor (d. 1576) |
| 86309 | July 31 | Birth | 1598 – Alessandro Algardi, Italian sculptor (d. 1654) |
| 86310 | July 31 | Birth | 1702 – Jean Denis Attiret, French missionary and painter (d. 1768) |