U.S. Air Force 2nd Lt. Peter Last, 633rd Civil Engineer Squadron operations engineer element officer in charge, ties a knot on a pipe during a Prime Base Engineer Emergency Force training at Joint Base Langley-Eustis, Va., April 20, 2017. The training took place at the obstacle and leadership reaction courses at Fort Eustis, Va., to help build morale and confidence. (U.S. Air Force photo/Airman 1st Class Kaylee Dubois)