“Medcap”, June 1969, showing Marines smoking and joking atop lumbering a 37-ton LVTP-5 (Landing Vehicle, Tracked, Personnel) amphibious armored fighting vehicle “somewhere in Vietnam.”
Note the sandbagged fighting position, complete with an M2 .50 cal HMG and an M1919 .30 cal LMG, and tarp sunshade.
Powered by a Continental V12, the LVTP-5 was good for about 20 mph on roads and a wallowing 4 knots on the water but could carry a platoon of Marines over the beach from as far as 30 miles offshore and withstand (some) small arms fire. Replaced in the 1970s by the AAVP-7A1, which itself has been the subject of various replacement programs for decades, the big amtrac is still reportedly in use in the Philipines.
MEDCAP, of course, was for the underappreciated Medical Civil Action Program, which provided much-needed medical care across South Vietnam during the American involvement in Southeast Asia. True hearts and minds type stuff that was underreported both then and now.