On January 1968, sighting the enemy, the door gunner aboard a Huey helicopter opens fire on a target below in the Mekong Delta.
An American soldier turns to give instructions as firing continues in front of him.
Two First Cavalry men support a wounded comrade near Khe Sanh in April 1968.
A helicopter rescues wounded soldiers from the battlefield. This type of evacuation was known as a dust-off.
American soldiers in Vietnam keep a lookout over Da Nang airforce base on November 1, 1965.
Two U.S. Marines search tunnels for signs of Viet Cong activity near Da Nang. The Viet Cong had an extensive network of underground tunnels that they used to launch attacks against U.S. forces.
U.S. Navy rockets flash from beneath the wings of a Phantom F4B during an attack on a Viet Cong position.
American Marines enjoy a quiet moment in their bunker near Khe Sanh.
The Navy's Patrol Air Cushion Vehicle (PACV) was introduced during the Vietnam War. It was used for assault missions, search and rescue, high-speed troop transportation and logistic support.
Soldiers pray with the army chaplain on the front lines of the Vietnam War.
Marines arrive by landing craft at Da Nang, where U.S. forces were stationed to mobilize against Viet Cong guerrillas.
A cargo plane sprays Agent Orange over a forest in North Vietnam. Agent Orange was a blend of herbicides used to defoliate forests where Viet Cong forces were based.
