CAMP GRAYLING, Mich. – A CH-47D Chinook with Bravo Company, 3rd Battalion, 238th Aviation Regiment prepares to transfer U.S. Marines with Echo Company, 4th Reconnaissance Battalion, 4th Marine Division, Marine Forces Reserve for their High Altitude-High Opening technique training at Camp Grayling Joint Maneuver Training Center, Michigan on August 2, 2017 during Exercise Northern Strike 17. The high-altitude, high-opening parachute insertion method allows Marines to covertly insert themselves onto the battlefield to conduct reconnaissance, acting as the eyes and ears for the commander. Exercise Northern Strike is a National Guard Bureau-sponsored training exercise that unites service members from multiple branches, states and coalition countries to conduct combined ground and air combat operations. (U.S. Marine Corps photo by Lance Cpl. Imari J. Dubose/Released).