Overview
Thuy Son, the water mountain, is the only one open to visitors and the only one with a lift, and its caves are the reason to come: Huyen Khong is a vaulted chamber with light falling through holes in the roof onto an altar, and the smaller caves hold Cham and Vietnamese carvings from different centuries. The hills were used as a Viet Cong field hospital during the American war, overlooking a US airbase. The marble quarrying that gave them their name is now banned to stop them being cut away.
Highlights
Take the lift up and the steps down; the steps are steep, uneven and slippery when wet. Huyen Khong cave is best between ten and noon, when the light shafts land on the altar. The stone carving village at the foot sells work made from imported marble now, not from the hills.