Airmen from the 28th Civil Engineer Squadron build a temper tent during a base operational readiness exercise at Ellsworth Air Force Base, S.D., Oct. 20, 2015. Base operational readiness exercises evaluate the wing's ability to meet wartime and contingency tasks of employing and sustaining forces, and maintaining the ability to survive and operate in a deployed location. (U.S. Air Force photo by Senior Airman Rebecca Imwalle/Released)