Early in 1968, North Vietnamese troops and the Viet Cong launched the largest battle of the Vietnam War, attacking more than 100 cities simultaneously with more than 80,000 fighters. After brief losses, U.S. and South Vietnamese forces regained lost territory, and dealt heavy losses to the North. Tactically, the offensive was a huge loss for the North, but it marked a significant turning point in public opinion and political support, leading to a drawdown of U.S. troop involvement, and eventual withdrawal in 1973. This photo essay, part two of a three-part series, covers the war years between 1968 and 1975. Tomorrow, in part 3, a more intimate look at the Vietnamese people in wartime by photographer Eddie Adams. Warning: Several of these photographs are graphic in nature.