September 15: Independence Day for Costa Rica, Guatemala, Honduras, Nicaragua and El Salvador (1821)
- 1644: Giovanni Battista Pamphili became Pope Innocent X.
- 1835: Aboard HMS Beagle, Charles Darwin reached the Galápagos Islands, where he began to develop his theories of evolution.
- 1916: Tanks, the "secret weapons" of the British Army during World War I, were first used in combat at the Battle of the Somme.
- 1935: Nazi Germany enacted the Nuremberg Laws, which deprived German Jews of citizenship, and adopted a new national flag emblazoned with a swastika.
- 1950: Korean war: U.S. armed forces landed at Incheon, Korea.
Recent days: September 14 – September 13 – September 12
More anniversaries: