U.S. Marine Corps 1st Sgt. Heroides Aguirre, center,

U.S. Marine Corps 1st Sgt. Heroides Aguirre, center, company first sergeant, salutes 1st Lt. Joseph Osborne, right, commanding officer, both with Headquarters and Service Company, 1st Battalion, 6th Marine Regiment, 2nd Marine Division (MARDIV), during a promotion ceremony 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)