The route begins in Saint-Imier, a watchmaking stronghold in the Bernese Jura, with its distinctive construction method. The townscape is known for parallel running streets and buildings with large windows to let a maximum of daylight in. Longines, the famous watchmaking factory, is still located here. The workshops and a museum are housed in the original buildings in the lower part of the town, directly on the Suze River. The route passes the factory, before it branches off in the direction of Combe Grède.

At first, the rock basins in the gorge appear to be almost impassable, but the well-built hiking trail is secured with ladders where necessary. These make the challenging, steep ascent easier than it looks. The native inhabitants of the nature preserve include chamois and marmots. The peace and quiet of the pristine environment and the variety of flora and fauna have been well-preserved. About 500 altitude meters higher up is the La Corne lookout, the highest point of the tour. The views from the cliffs down into the Combe Grède gorge and the valley of Saint-Imier are amazing.

On the way down you come across the Métairie des Plânes restaurant. For simple meals, these typical mountain inns often use home-grown products. The route continues to the ruins of Ergüel and crosses the tree-covered meadows, the characteristic landscapes of the Jura region. Château d'Erguël is the best preserved castle ruin in the Bernese Jura, but its origins are not completely clear, even now. The Bishop of Basel, Burkhard von Fenis, probably used it in the early Middle Ages during the conflict between the dioceses of Basel and Lausanne. Some legends are also circulating about the ruins, such as the one of the “Dame Blanche d’Erguël”. According to the story, her ghost has been haunting the ruins to this day. The path then zigzags down to the Suze River. From here it’s just a short distance to get to the train station of Sonvilier.