U.S. Marine Corps Pfc. Caleb Mattssonboze, a machine gunner with Weapons Company, 2nd Battalion, 4th Marine Regiment, provides security in the early morning during a Mountain Warfare Exercise at Marine Corps Mountain Warfare Training Center near Bridgeport, Calif., June 20, 2014.
(DoD photo by Lance Cpl. Ashton Buckingham, U.S. Marine Corps/Released). Original public domain image from Flickr