Citations, photographs and other relics belonging to Master Sgt. William Pook, a reservist assigned to the 633rd Civil Engineer Squadron, are displayed during his retirement ceremony at the squadron’s Emergency Management flight warehouse at Langley Air Force Base, Va., Sept. 23, 2011. Pook, one of a handful of Vietnam veterans still serving, retired after 40 years in the Air Force. (U.S. Air Force photo by Senior Airman Jason J. Brown/Released)