Combat engineers and infantrymen with 3rd Battalion,

Combat engineers and infantrymen with 3rd Battalion, 5th Marine Regiment, 1st Marine Division, build explosive charges during a cross-training drill aboard Camp Pendleton, Calif., Oct. 4, 2016. During the training the Marines built breaching charges, field-expedient bangalores, and demolition charges in preparation for upcoming deployments. 1st Marine Division is employed as the ground combat element of I Marine Expeditionary Force and provides the ground combat forces necessary for ship to shore forcible entry operations. (U.S. Marine Corps photo by Lance Cpl. Bradley J. Morrow)