Tech. Sgt. Leslee Williams (right) climbs up one of the Assault Course obstacles as Staff Sgt. Alexr Andriyanov (left) descends on the other side during a practice run on the Assault Course at the U.S. Air Force Academy, Colo., May 18, 2010. Both are Guardian Challenge 2010 competitors from the Space and Missile Systems Center's 61st Security Forces Squadron at Los Angeles Air Force Base. (Photo by Lou Hernandez)