Twentynine Palms, Calif., October 2001: Cpl. Roger Zion, left, Staff Sgt. Nicholas Ballowe, center, and Sgt Nathan Butts — seemingly framed by a heart made out of concertina wire — scan a map to locate their next desert destination. The Marines are taking part in a combined arms exercise at the Marine Corps’ Air, Ground Combat Center in the Californian high desert to prepare them for any future combat in Afghanistan.