A U.S. Army Ranger assigned to 2nd Platoon, Bravo Company, 3rd Battalion, 75th Ranger Regiment, provides security in a Humvee's gunner's turret during night operation training at Fort Knox, Ky., April 26, 2014. Rangers go through intensified combat simulation to prepare for future operations.(U.S. Army photo by Spc. Arthur Ruepong/Released)