U.S. Air Force Airmen from the 633rd Civil Engineer Squadron Prime Base Emergency Engineer Force (BEEF) search for their next marker during land-navigation training at Fort Eustis, Va., Oct. 16, 2013. Because Prime BEEF units partner with all branches of the military, land navigation is vital towards mission success in deployed locations. (U.S. Air Force photo by Airman 1st Class Austin Harvill/Released)