March 21: Benito Juárez Day in Mexico, Norouz in Iran, World Poetry Day
- 1556 - Archbishop of Canterbury Thomas Cranmer was burnt at the stake.
- 1800 - Pius VII was crowned Pope in Venice with a temporary papal tiara made of papier-mâché.
- 1804 - Code Napoléon was adopted as French civil law.
- 1935 - Shah Reza Pahlavi formally asked the international community to call Persia by its native name, Iran, which means 'Land of the Aryans'.
- 1990 - Formerly known as South-West Africa, Namibia gained independence from South Africa, with Sam Nujoma swearing in as the first President.