Source ferrugineuse

Ventron has a ferruginous spring not to be missed: from the center of Ventron, drive 3 km in the direction of Thann, then turn left at a hairpin bend, direction "Auberge de la Chaume du Grand Ventron". After 2 km, you'll reach the refuge des Places, where you can park. The spring is on your right as you descend 30 m. As it passes through one or more veins of iron oxide on its underground journey, the spring becomes charged with ferric ions which, on contact with the air, give it its characteristic brick color. There's also an on-site wish tree, on which visitors can hang scraps of fabric and handkerchiefs to see their wishes come true.