Wikipedia:Selected anniversaries/August 21
August 21: Independence Day in Latvia (1991), Ninoy Aquino Day in the Philippines.
- 1772 - A bloodless coup led by Gustav III was completed with the adoption of a new Instrument of Government.
- 1831 - Nat Turner led a slave revolt in Southampton County, Virginia.
- 1911 - Mona Lisa (pictured), an oil painting by Leonardo da Vinci, was stolen from the Louvre Museum in Paris.
- 1976 - Operation Paul Bunyan was carried out in response to the Axe Murder Incident in the Korean Demilitarized Zone, almost triggering a second Korean War.
- 1986 - A limnic eruption from Lake Nyos in Cameroon killed up to 1,800 people and 3,500 livestock in nearby villages.