In the remote alpine village of Vals-les-Bains, in Switzerland, a mountain hot spring has been has enjoyed for over a century. In the 1990s, however, as the tourist complex and spa were declining, the community decided to construct a new facility. Designed by Peter Zumthor, the building is the form of a parallelepiped, which seems half submerged in the mountain face. From the route that crosses the village, all that can be seen is a large wall of flat stones, with large openings resembling fissures. Closer up, foliated strata of gneiss¿the material traditionally used in the roofs of the chalets¿can be seen, which form horizontal bands of identical widths. Inside the thermal baths, along the sixty-metre long walls and terraces, are a stone clock and precise spatial configurations. The building echoes the idea of thermal baths with an astute juxtaposition of the various states of water, of stone¿everywhere the same, immutable and reassuring¿and variations of light, creating an experience of both sensuality and spirituality.