The guy that took us on a tour of this site was a diplomatic blend of all of the above (there were a lot of Americans in our group).
This little hatch on the jungle floor was/is an opening of a 220km network of tunnels that the Viet Cong used to hide in from the Americans and the Communists.
Kyla, showing more courage than me.
These passages led to multi-floor hospitals, bedrooms, ammo stores, kitchens, and living quarters.
Wikipedia asserts that "the role of the tunnel systems should not be underestimated in its importance to the Viet Cong in resisting American operations and protracting the war, eventually culminating in an American withdrawal."
I had a serious anxiety attack going in this tunnel, but Edna and the kids thought it was fun (the lights weren't on).