Hovering U.S. Army helicopters pour machine gun fire into tree line to cover the advance of Vietnamese ground troops in an attack on a Viet Cong camp 18 miles north of Tay Ninh on March 29, 1965, which is northwest of Saigon near the Cambodian border. Combined assault routed Viet Cong guerrilla force. (Photo by Horst Faas/AP Photo)
