Hovering U.S. Army helicopters pour machine-gun fire into the tree line to cover the advance of South Vietnamese ground troops as they attack a Viet Cong camp eighteen miles north of Tay Ninh, near the Cambodian border, March 1965. (AP Photo/Horst Faas)
FOR ONE-TIME EDITORIAL USE ONLY IN CONNECTION WITH THE AP BOOK AND GUARDIAN EXHIBIT “Vietnam: The Real War”