U.S. Marine Cpl. John F. Espinoza, top, demonstrates

U.S. Marine Cpl. John F. Espinoza, top, demonstrates a cliff assault during Mountain Exercise 2014 aboard Marine Corps Mountain Warfare Training Center in Bridgeport, Calif., Sept. 1, 2014. Espinoza is a squad leader with 2nd Platoon, Lima Company, 3rd Battalion, 1st Marine Regiment. Marines with 3rd Battalion, 1st Marine Regiment will become the 15th Marine Expeditionary Unit’s ground combat element in October. Mountain Exercise 2014 develops critical skills the battalion will need during deployment. (U.S. Marine Corps photo by Sgt. Emmanuel Ramos/Released)