Wayne Simmons, a firefighter at Naval Station Everett, Wash., and Lt. Steve Mabes, a police officer at the facility, participate in a 9/11 memorial ceremony 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. (U.S. Navy photo by Mass Communication Specialist 2nd Class Jeffry A. Willadsen/Released)