Marines from India Company, 3rd Battalion, 25th Marine Regiment, watch as the crew of an amphibious assault vehicle begin to close all of the hatches of the vehicle to prepare for a lake crossing during Exercise Northern Strike at Camp Grayling, Mich., Aug. 7, 2018. Camp Grayling, the largest National Guard center in the country covering 147,000 acres, offers many large artillery, mortar, tank ranges and maneuver courses. (U.S. Marine Corps photos by Cpl. Niles Lee)