U.S. Air Force Staff Sgt. Louis Diaz-Garcia, a military working dog handler assigned to the 379th Expeditionary Security Forces Squadron, and his military working dog Roy take a walk under the runway lights at Al Udeid Air Base, Qatar, May 4, 2017. Diaz-Garcia and Roy are unwinding after participating in a detection exercise designed to give the K-9 teams an opportunity to familiarize themselves with the general layout and specific challenges associated with detection aboard an aircraft. (U.S. Air Force photo by Tech. Sgt. Bradly A. Schneider/Released)