Two hijacked aircraft crash into the World Trade Center in New York City, while a third smashes into The Pentagon in Arlington County, Virginia, and a fourth into a field near Shanksville, Pennsylvania, in a series of coordinated suicide attacks by 19 members of al-Qaeda. A total of 2,996 people are killed.
Historic National Prayer Service held at Washington National Cathedral for victims of the September 11 attacks. A similar service is held in Canada on Parliament Hill, the largest vigil ever held in the nation's capital.
The Global War on Terrorism begins as a result of the September 11 attacks. The U.S. invasion of Afghanistan initiates with an air assault and covert operations on the ground.