Chek, a Fort Eustis Military Working dog, waits for his turn to go through an obstacle course during the 50th Vietnam War Commemoration at Fort Eustis, Va., May 16, 2015. Military working dogs were utilized in the Vietnam War just as they are now. The MWDs in Vietnam were trained for jungle combat, day and night time scouting, detecting tunnels, mines and other items. (U.S. Air Force photo by Senior Airman Kimberly Nagle/Released)