U.S. Army National Guard and U.S. Air Force Air National Guardsman, search for simulated wounded and dead at Muscatatuck Training Center, Camp Atterbury, Indiana, on May 12, 2007, during Exercise Vigilant Guard, a joint military and civilian training exercise simulating the detonation of nuclear devices in a metropolitan area. (U.S. Army photo by SGT. Michael Krieg) (Released)