Osan honors 9/11 first responders
U.S. Air Force Staff Sgt. Krystopher Morgan, 51st Civil Engineer Squadron fire and emergency services flight lead firefighter, sounds a bell during a 9/11 memorial ceremony at Osan Air Base, Republic of Korea, Sept. 11, 2018. Sounding the four fives is a custom in which a bell is struck five times, in four series, to announce the death of a firefighter in the line of duty. (U.S. Air Force photo by Senior Airman Kelsey Tucker)