| 94321 | August 20 | Event | 1083 – Canonization of the first King of Hungary, Saint Stephen and his son Saint Emeric. |
| 94322 | August 20 | Event | 1308 – Pope Clement V pardons Jacques de Molay, the last Grand Master of the Knights Templar, absolving him of charges of heresy. |
| 94323 | August 20 | Event | 1391 – Konrad von Wallenrode becomes the 24th Grand Master of the Teutonic Order. |
| 94324 | August 20 | Event | 1467 – The Second Battle of Olmedo takes places as part of a succession conflict between Henry IV of Castile and his half-brother Alfonso, Prince of Asturias. |
| 94325 | August 20 | Event | 1519 – Philosopher and general Wang Yangming defeats Zhu Chenhao, ending the Prince of Ning rebellion against the reign of the Ming dynasty's Zhengde Emperor. |
| 94326 | August 20 | Event | 1672 – Former Grand Pensionary Johan de Witt and his brother Cornelis are brutally murdered by an angry mob in The Hague. |
| 94327 | August 20 | Event | 1707 – The first Siege of Pensacola comes to end with the failure of the British to capture Pensacola, Florida. |
| 94328 | August 20 | Event | 1710 – War of the Spanish Succession: A multinational army led by the Austrian commander Guido Starhemberg defeats the Spanish-Bourbon army commanded by Alexandre Maître, Marquis de Bay in the Battle of Saragossa. |
| 94329 | August 20 | Event | 1775 – The Spanish establish the Presidio San Augustin del Tucson in the town that became Tucson, Arizona. |
| 94330 | August 20 | Event | 1794 – Battle of Fallen Timbers: American troops force a confederacy of Shawnee, Mingo, Delaware, Wyandot, Miami, Ottawa, Chippewa, and Potawatomi warriors into a disorganized retreat. |
| 94331 | August 20 | Event | 1858 – Charles Darwin first publishes his theory of evolution through natural selection in The Journal of the Proceedings of the Linnean Society of London, alongside Alfred Russel Wallace's same theory. |
| 94332 | August 20 | Event | 1866 – President Andrew Johnson formally declares the American Civil War over. |
| 94333 | August 20 | Event | 1882 – Tchaikovsky's 1812 Overture debuts in Moscow, Russia. |
| 94334 | August 20 | Event | 1910 – The Great Fire of 1910 (also commonly referred to as the "Big Blowup" or the "Big Burn") occurs in northeast Washington, northern Idaho (the panhandle), and western Montana, burning approximately 3 million acres (12,000 km2). |
| 94335 | August 20 | Event | 1914 – World War I: German forces occupy Brussels. |
| 94336 | August 20 | Event | 1920 – The first commercial radio station, 8MK (now WWJ), begins operations in Detroit. |
| 94337 | August 20 | Event | 1926 – Japan's public broadcasting company, Nippon Hōsō Kyōkai (NHK) is established. |
| 94338 | August 20 | Event | 1938 – Lou Gehrig hits his 23rd career grand slam, a record that stood for 75 years until it was broken by Alex Rodriguez. |
| 94339 | August 20 | Event | 1940 – In Mexico City, Mexico exiled Russian revolutionary Leon Trotsky is fatally wounded with an ice axe by Ramón Mercader. He dies the next day. |
| 94340 | August 20 | Event | 1940 – World War II: British Prime Minister Winston Churchill makes the fourth of his famous wartime speeches, containing the line "Never was so much owed by so many to so few". |
| 94341 | August 20 | Event | 1944 – World War II: 168 captured allied airmen, including Phil Lamason, accused by the Gestapo of being "terror fliers", arrive at Buchenwald concentration camp. |
| 94342 | August 20 | Event | 1944 – World War II: The Battle of Romania begins with a major Soviet Union offensive. |
| 94343 | August 20 | Event | 1950 – Korean War: United Nations repel an offensive by North Korean divisions attempting to cross the Nakdong River and assault the city of Taegu. |
| 94344 | August 20 | Event | 1955 – In Morocco, a force of Berbers from the Atlas Mountains region of Algeria raid two rural settlements and kill 77 French nationals. |
| 94345 | August 20 | Event | 1960 – Senegal breaks from the Mali Federation, declaring its independence. |
| 94346 | August 20 | Event | 1962 – The NS Savannah, the world's first nuclear-powered civilian ship, embarks on its maiden voyage. |
| 94347 | August 20 | Event | 1965 – Keene, NH Episcopal seminarian Jonathan Daniels, 26, is martyred murdered by shotgun at point-blank range in Hayneville, Alabama, by an unpaid sheriff's deputy, sacrificing his life for young black activist Ruby Sales whom he pushed out of the way |
| 94348 | August 20 | Event | 1968 – Soviet Union-dominated Warsaw Pact troops invade Czechoslovakia, crushing the Prague Spring. |
| 94349 | August 20 | Event | 1975 – Viking program: NASA launches the Viking 1 planetary probe toward Mars. |
| 94350 | August 20 | Event | 1977 – Voyager program: NASA launches the Voyager 2 spacecraft. |