Europe's largest subterranean lake that can be sailed upon lies between Sion and Sierre. The water grotto is easily accessible and there is a boat tour for viewing it. The guides on the boat tell visitors about the history of the cave and its geology.
Already Neanderthal men were here where today a cableway sweeps visitors up and over the rugged rocks of the once populated Ebenalp caves - and a great departure point for various discoveries.
If brooks and rivers run only sluggishly above ground, hydropower is nearly impossible to harness. That is why the inhabitants of the valley of Le Locle began to use subterranean streams. This is how the cave mills of "Col-des-Roches" arose.