Around 2km east along Rte 1C, Tham Pha Thok is a series of caves in a limestone cliff where villagers and Pathet Lao eluded bombing during the Second Indochine War. The first cave is around 30m high and accessed by wooden stairway. Continue to the second, somewhat-claustrophobic cave, 300m along a dark passage through the cliff.
We recommend bringing your own torch rather than renting a weak one.