U.S. Marines with 1st Combat Engineer Battalion empty a wheelbarrow while building a terrain model of Marine Corps Air Ground Combat Center Twentynine Palms aboard Camp Pendleton, Calif., Apr. 23, 2014. The terrain model was constructed for a Rehearsal of Concept brief for Exercise Desert Scimitar. (U.S. Marine Corps photo by Pfc. Dominique Green, 1st Marine Division Combat Camera/Released)