Marines with the 15th Marine Expeditionary Unit, build a human pyramid to negotiate a wall while participating in a team building obstacle course at Arta Beach, Djibouti, Dec. 11, 2012. The 15th MEU is deployed as part of the Peleliu Amphibious Ready Group as a U.S. Central Command theater reserve force, providing support for maritime security operations and theater security cooperation efforts in the U.S. 5th Fleet area of responsibility.