U.S. Army Rangers from 2nd Platoon, Charlie Company, 3rd Battalion, 75th Ranger Regiment, wait to board a CH-47 Chinook helicopter during night operation training, Fort Knox, Ky., April 23, 2014. Rangers are constantly training to maintain the highest level of tactical proficiency. The training was to ensure all Soldiers are proficient in warrior skills and tasks in preparation for their upcoming deployment.(U.S. Army photo by Spc. Arthur Ruepong/Released)