There are several climbing opportunities around Erstfeld. Right after the bridge are parking lots. From there walk towards the Autobahn underpass. Right after the Underpass is the access to Beton Mattli. Follow the footpath marked with red and pink till you are at the power pole. Head up the boulders. Red markings should show the way. When you are back in the forest, you are just below of Zwatzli. Und nah gah innägumpä is left and up. Cairn are marking the way.
