Pak Ou Caves.

Set into a towering limestone cliff where the Nam Ou and Mekong rivers meet, the Pak Ou Caves are a dramatic spiritual landmark best reached by a scenic boat ride from Luang Prabang. This sacred site consists of two caverns packed with thousands of Buddha statues left by pilgrims, villagers, and royalty over the centuries. The lower cave, Tham Ting, features sunlit shelves and ledges crowded with gilded, wooden, and bronze figures overlooking the water. A steep climb leads to the darker, atmospheric upper cave, Tham Theung, which requires a torch to explore. Originally used for animist nature worship before transforming into a Buddhist sanctuary, the caves still function as a working pilgrimage site where locals deposit retired or damaged images, creating a dense, living archive of Lao devotion.