Both photos are from the Abel Collection Top,
a covey of Boeing Vertol CH-46s carrying elements of the 4th Marines
into a landing zone just south of the DMZ is viewed through the door
of one of the helicopters. The outline of the helicopter's machine gun
can be seen at the opening. In the bottom photo, Marines in the same
operation, now on the ground, wade through a stream whose water comes
up to their waists.
Both photos are from the Abel Collection