“South Vietnamese forces follow after terrified children, including 9-year-old Kim Phuc, center, as they run down Route 1 near Trang Bang after an aerial napalm attack on suspected Viet Cong hiding places on June 8, 1972. A South Vietnamese plane accidentally dropped its flaming napalm on South Vietnamese troops and civilians. The terrified girl had ripped off her burning clothes while fleeing. The children from left to right are: Phan Thanh Tam, younger brother of Kim Phuc, who lost an eye, Phan Thanh Phouc, youngest brother of Kim Phuc, Kim Phuc, and Kim's cousins Ho Van Bon, and Ho Thi Ting. Behind them are soldiers of the Vietnam Army 25th Division.” (AP Photo/Nick Ut)

“In this June 18, 1965 file photo, an unidentified U.S. Army soldier wears a hand lettered "War Is Hell" slogan on his helmet, in Vietnam. 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/Horst Faas, File)

“In this June 15, 1967 file photo, American infantrymen crowd into a mud-filled bomb crater and look up at tall jungle trees seeking out Viet Cong snipers firing at them during a battle in Phuoc Vinh, north-Northeast of Saigon in Vietnam's War Zone D. 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)

“In this March 17, 1973 file photo, released prisoner of war Lt. Col. Robert L. Stirm is greeted by his family at Travis Air Force Base in Fairfield, Calif., as he returns home from the Vietnam War. 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/Sal Veder, File)

“South Vietnamese Gen. Nguyen Ngoc Loan, chief of the national police, fires his pistol into the head of suspected Viet Cong officer Nguyen Van Lem (also known as Bay Lop) on a Saigon street Feb. 1, 1968, early in the Tet Offensive.” (AP Photo/Eddie Adams)

“In this April 29, 1975 file photo, U.S. Navy personnel aboard the USS Blue Ridge push a helicopter into the sea off the coast of Vietnam in order to make room for more evacuation flights from 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/File)

“In this April 30, 1975 file photo, a North Vietnamese tank rolls through the gate of the Presidential Palace in Saigon, signifying the fall of South Vietnam. 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/File)

“In this January 1966 file photo, First Cavalry Division medic Thomas Cole, from Richmond, Va., looks up with one uncovered eye as he treats a wounded Staff Sgt. Harrison Pell during a firefight in the Central Highlands in Vietnam, between U.S. troops and a combined North Vietnamese and Vietcong force.” (AP Photo/Henri Huet, File)

“In this Jan. 1, 1966 file photo, women and children crouch in a muddy canal as they take cover from intense Viet Cong fire at Bao Trai, about 20 miles west of Saigon, Vietnam. 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/Horst Faas, File)

“Quang Duc, a Buddhist monk, burns himself to death on a Saigon street June 11, 1963 to protest alleged persecution of Buddhists by the South Vietnamese government.” (AP Photo/Malcolm Browne)