U.S. Marines with the 11th Marine Expeditionary Unit bow their heads aboard the amphibious transport dock ship USS San Diego (LPD 22) in the U.S. 7th Fleet area of responsibility Sept. 11, 2014, during a moment of silence in remembrance of the victims of the 9/11 terrorist attacks. 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.