Viamala

Viamala or Via Mala is an ancient and notorious section of a path along the river Hinterrhein between Zillis-Reischen and Thusis in the Canton of Graubünden. This narrow gorge was the most serious obstacle on the approach to two mountain passes: the Splügen and the San Bernardino.

There was a path through the Viamala already in Roman antiquity, though it is not clear whether it was only a foot and bridle path, or could also be used by wagons. Two access paths met at the northern entrance to the Viamala, which the Romans traversed by means of several rock galleries cut into the walls on the left side of the gorge. Presumably somewhere below today's automobile bridge and near the pedestrian bridge the Romans constructed a wooden bridge crossing over to the right side of the Rhine, routing traffic via Reischen to Zillis.

Wikipedia