Vietnam War(1964-75): Many of the 8.8 million who served in uniform were draftees; 7.6 million are alive today.

Kim Ki Sam/AP/File
US Marines of the 3rd Battallion, 4th Marines, crouch in the cover of a pagoda entrance as their patrol moves through a village along the Ben Hai river in the southern sector of the DMZ in South Vietnam, on May 22, 1967.