Staff Sgt. Scott Greco, 28th Civil Engineer Squadron explosive ordinance disposal technician, participates in the Rucksack March 10K at Ellsworth Air Force Base, S.D., March 11, 2016. Participants were required to carry a minimum of 35 pounds in their rucks during the event. (U.S. Air Force photo by Airman 1st Class Denise M. Nevins/Released)