Staff Sgt. Timothy Allen, 90th Security Support Squadron training instructor, helps a defender with her mask during the Crow Creek Challenge on F.E. Warren Air Force Base, Wyo., Sept. 22, 2017. This is the 23rd year the Crow Creek Challenge has put the 90th Missile Wing’s defenders’ mental and physical capabilities to the test. (U.S. Air Force photo by Airman 1st Class Breanna Carter)