U.S. Marines in I Corps in the northern provinces of South Vietnam, constantly patrol their operational area in search of the enemy.

Here, "Leathernecks" move out with amphibious tractors (Amtracs) as support.

For some distance, the men and vehicles stick to roads, then later move to the grasslands.

When fortified trenchlines and bamboo-reinforced bunkers are found by the patrol nearby tanks fire 90mm explosive rounds into enemy positions in the treeline.

Some scattered Viet Cong soldiers return small arms fire at Marines deployed near the tanks and Amtracs.

Marine jet fighters are called in to bomb the enemy positions and cut off their routes of escape. Laden with bombs and rockets, the jet lace the enemy locations in run after run.

the unit sustained a casualty and a Medevac (Medical evacuation) helicopter is called to evacuate the wounded "Leatherneck".

The "Airborne Ambulance" files low across a stretch of Vietnamese grassland, on its way to the hastily secured landing zone (LZ). As the chopper whirls into the LZ, stretcher bearers, running is a low crouch, hustle their wounded comrade aboard. The helicopter lifts off and heads for the nearest field hospital where the wounded man will receive man will receive prompt medical attention.