A Marine rifleman, Alpha Company, 1st Battalion, 6th

A Marine rifleman, Alpha Company, 1st Battalion, 6th Marine Regiment, 2nd Marine Division (MARDIV), helps provide security as his company is halted in the mountains before executing a rock cliff assault at landing zone sardine rock, during basic mountain training for Mountain Exercise 5-15 at the Marine Corps Mountain Warfare Training Center, Bridgeport, Calif., Sept. 17, 2015. Marines participate in a month-long field exercise focusing on core mission essential tasks such as assault climbing, animal packing and small unit movements, to strengthen expeditionary high altitude warfare tactics in a mountainous environment against a hybrid threat, as they prepare for world-wide deployment. (U.S. Marine Corps photo by Cpl. Kelly L. Street, 2D MARDIV COMCAM/Released)