U.S. Marine Corps Gunnery Sgt. Guadalupe E. Pineda,

U.S. Marine Corps Gunnery Sgt. Guadalupe E. Pineda, far left, platoon sergeant, 2nd Combat Engineer Battalion, 2nd Marine Division (MARDIV), currently attached to 1st Battalion, 6th Marine Regiment, mentors Marines in knot tying prior to the start of Mountain Exercise 5-15 at the Marine Corps Mountain Warfare Training Center, Bridgeport, Calif., Sept. 2, 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)