President Barack Obama lays a Presidential challenge coin on a grave in Section 60 at Arlington National Cemetery in Arlington, Va., May 30, 2011. Section 60 is reserved for military personnel who have lost their lives while fighting in Afghanistan and Iraq.

President Barack Obama lays a Presidential challenge coin on a grave in Section 60 at Arlington National Cemetery in Arlington, Va., May 30, 2011. Section 60 is reserved for military personnel who have lost their lives while fighting in Afghanistan and Iraq.