U.S. Navy Operations Specialist 1st Class Gerald Crawford, assigned to the U.S. Naval War College, rings a bell during a 9/11 commemoration ceremony at Naval Station Newport, R.I., Sept. 11, 2014. Terrorists hijacked four passenger aircraft Sept. 11, 2001. Two of the aircraft were deliberately crashed into the World Trade Center in New York; one was crashed into the Pentagon; the fourth crashed near Shanksville, Pa. Nearly 3,000 people died in the attacks.