Senior Airman Kurt Nelson, 28th Civil Engineer Squadron structures apprentice, prepares to cross a make-shift bridge during a leadership reaction course at the South Dakota National Guard West Camp Rapid training facility, Rapid City, S.D., June 17, 2016. The purpose of this obstacle was to move all the materials given from one side to another without dropping any of them on the ground below them in 20 minutes. (U.S. Air Force photo by Airman 1st Class Denise M. Nevins/Released)