U.S. Marines with 5th Marine Regiment and Headquarters Company, 1st Battalion, 5th Marines scan for contaminants during a Chemical, Biological, Radioactive, Nuclear (CBRN) drill as a part of Exercise STEEL KNIGHT 2014 aboard Marine Corps Air Ground Combat Center Twentynine Palms, Calif., Dec. 14, 2013. Steel Knight enables 1st Marine Division to test and refine its command and control capabilities by acting as the headquarters element for a forward-deployed Marine Expeditionary force. (U.S. Marine Corps photo by Cpl. Justin A. Bopp, 1st Marine Division Combat Camera / Released)