September 11: Patriot Day in the United States
- 1649 – Cromwellian conquest of Ireland: Oliver Cromwell'sNew Model Army ended the Siege of Drogheda, took over the town and massacred its garrison.
- 1814 – The Battle of Plattsburgh ended Britain's final invasion of the northern states during the War of 1812.
- 1893 – On the opening day of the first Parliament of the World's Religions in Chicago, Swami Vivekananda (pictured) introducedHinduism to the United States.
- 1914 – During the First World War, the Australian Naval and Military Expeditionary Force invaded German New Guinea, winning the Battle of Bita Paka.
- 2012 – Garment factories in the Pakistani cities of Karachi and Lahorecaught fire, leaving 315 dead.