U.S. Marine Corps Sgt. Jonathan W. Jacobson, instructor

U.S. Marine Corps Sgt. Jonathan W. Jacobson, instructor team leader, Marine Corps Mountain Warfare Training Center (MCMWTC), supervises Marines with Charlie Company, 1st Battalion, 6th Marine Regiment, 2nd Marine Division (MARDIV), as they practice various techniques they learned on how to cross a stream effectively and safely, Mountain Exercise 5-15 at MCMWTC, 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)