These two caves can be visited from Thakhek. Tham Pha Fa, the "Buddha's cave", was discovered in 2004 by a local peasant searching for bat guano. It is home to 229 old Buddhas and quickly became a place of pilgrimage. Less venerated but even more spectacular, the neighbouring Tham Pasuam (Tham Nong Paseum) can be explored by kayak, preferably during the dry season, when visitors can travel 400m along its underground river to the impressive pillar room, with its draperies of stalactites.