U.S. Air Force bombs create a curtain of flying shrapnel and debris barely 200 feet beyond the perimeter of South Vietnamese ranger positions defending Khe Sanh during the siege of the U.S. Marine base, March 1968. The photographer, a South Vietnamese officer, was badly injured when bombs fell even closer on a subsequent pass by U.S. planes. (AP Photo/ARVN, Maj. Nguyen Ngoc Hanh)