U.S. Marine Corps Staff Sgt. David K. Mwaura Jr., center

U.S. Marine Corps Staff Sgt. David K. Mwaura Jr., center left, instructor team leader, Marine Corps Mountain Warfare Training Center (MCMWTC), briefs Marines from Bravo Company before they begin a day land navigation class, during basic mountain training, MCMWTC, Bridgeport, Calif., Sept. 10, 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)