FILE - In this June 17, 1967 file photo, medic James E. Callahan of Pittsfield, Mass., treats a U.S. infantryman who suffered a head wound when a Viet Cong bullet pierced his helmet during a three-hour battle in war zone D, about 50 miles northeast of Saigon. The war ended on April 30, 1975, with the fall of Saigon, now known as Ho Chi Minh City, to communist troops from the north. (AP Photo/Henri Huet, File)