U.S. Marines with Charlie Company, 1st Battalion, 6th

U.S. Marines with Charlie Company, 1st Battalion, 6th Marine Regiment, 2nd Marine Division (MARDIV), break the surface of the water after being submerged, simulating extreme water conditions, while maintaining their positions in a stream crossing technique, during basic mountain training for Mountain Exercise 5-15 at the Marine Corps Mountain Warfare Training Center, Bridgeport, Calif., Sept. 14, 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)