Around 2km east along remarkably quiet Rte 1C, the horizon's array of towering karst formations reaches a brief but particularly impressive climax. Just beyond, Tham Pha Thok is a series of caves in an abrupt limestone cliff. This is where villagers and much of the Pathet Lao's Luang Prabang provincial government lived during the Second Indochina War to avoid American bombing. The first and most obvious cave is around 30m above ground level, accessed by a lichen-crusted wooden stairway. Much smaller but more exciting to visit (unless you're claustrophobic) is a second cave 300m around the cliff. Home to the region's main bank between 1968 and 1974, it's accessed through a narrow, twisting former siphon passage. It's pitch black inside the caves so bring a head-torch or rent one for 5000K at the ticket booth.
