Airmen don their gas masks and complete a set of workouts to include overhead sandbag presses during the Crow Creek Challenge, Sept. 6, 2019, at F. E. Warren Air Force Base, Wyo. The heavy bags were also used in other activities like a high-crawl bag toss and numerous calisthenic workouts. This obstacle was just one of many physical obstacles security forces members took part in during the challenge. (U.S. Air Force photo by Senior Airman Nicole Reed)