Marines with Company E, 2nd Battalion, 6th Marine Regiment, 2nd Marine Division provide security while their squad clears a building during a simulated assault on a combat town aboard Camp Lejeune, N.C., Dec. 4, 2014. While moving from building to building the Marines encountered resistance in the form of fellow Marines from 1st Battalion, 8th Marine Regiment acting as opposition forces. (Marine Corps photo by Lance Cpl. David N. Hersey/Released)