Park your vehicle next to the old quarries (on the main road, turn right at the Buhl traffic lights, then left, 300 metres further on and finally left again).
Follow the red circles. The quarries are also signposted.
(S/E) The route begins by taking Rue du Réservoir, which quickly turns into a path.
(1) Pass the reservoir that supplies Buhl with drinking water, where you can fill your water bottles.
(2) A little further on, turn left, still following the red circles. After several intersections, the path begins to climb steeply with small switchbacks. You will quickly arrive at the quarries.
(3) Take the time to admire the red sandstone and the old infrastructure that was used to extract it (I think there are some information panels).
Continue along the path through the quarries until you reach a forest track.
(4) Then turn left towards the Dreibannstein pass (537m).
(5) At the pass, take the path on the left marked with solid blue circles. Follow it, and it will take you back to the starting point, winding through the forest and offering beautiful views of the Grand Ballon at times. (S/E).
