There are three(?) places in Vietnam where the underground tunnel-villages of the Viet Cong have been preserved, but this is the only one that hasn't been modified for easier access for tourists. There have been changes, most notably to re-enforce the entrances to prevent collapses, but the tunnels are still the incredibly claustrophobic original size carved out of clay with only marginally better lighting than they had in the late sixties when an entire village of 500 lived in here. Lu, the woman seen in the tunnel above, is 161 cm or 5'3". She could stand up straight most places, but I was crouched over almost everywhere and turning around presented a challenge with a backpack on. There were "living quarters" carved into the sides of the tunnels - holes six feet deep by five feet wide and four feet tall that would "house" five or six people. One toilet for five hundred people. All entrances disguised, many leading to a forested hillside facing the sea.