Erosion has created an immense, pale yellow rock basin that is growing larger every year. It is well worth admiring this phenomenon of nature. The circular route follows the (mostly dry) bed of the Wildbach to the Bhutan Bridge and the Güetji viewing pulpit. Return to Susten along the other side of the trench.
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.