This is a list of selected August 12 anniversaries that appear in the "On this day" section of the Main Page. To suggest a new item, in most cases, you can be bold and edit this page. Before doing so, please review the selected anniversaries guidelines. If your suggestion is potentially controversial or relates to a day currently or soon to appear on the Main Page, post it on the talk page instead.
Please note:
- Events listed on the Main Page are selected based on article quality and to provide a diverse range of topics, rather than solely on the importance or significance of the events.
- Only four or five events are featured each day; therefore, not all important or significant events can be included.
- An event is generally excluded if it is already the subject of the scheduled featured article or picture of the day.
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August 12: Mother's Day and Queen Sirikit's Birthday in Thailand; International Youth Day
- 1099 – The First Crusade concluded with the Battle of Ascalon and Fatimid forces under Al-Afdal Shahanshah retreating to Egypt.
- 1676 – Praying Indian John Alderman shot and killed King Philip, the Wampanoag war chief, ending King Philip's War.
- 1877 – American astronomer Asaph Hall discovered Deimos, the smaller of the two moons of Mars.
- 1953 – The first Soviet thermonuclear bomb, Joe 4, was detonated at Semipalatinsk, Kazakh SSR.
- 1981 – The IBM Personal Computer (pictured), the original version and progenitor of the IBM PC compatible hardware platform was introduced.
- 1985 – Japan Airlines Flight 123 crashed into the ridge of Mount Takamagahara in Gunma Prefecture, Japan, killing 520 of 524 on board in the world's worst single-aircraft aviation disaster.