The "Sarrasinières" are underground passages located on the banks of the ancient Rhône valley. This is a vaulted gallery perpendicular to the river. It was a 13 km road composed of 2 separate twin galleries coming from Lyon to the castleof Miribel via Neyron. They would have allowed people to walk on them and would have been used as aqueducts. Little remains of the "Sarrasinières". There are many explanations about the origin of the name. The most certain is given by the following: the" Sarrasinières" would come from" Césarinières" ( Caesar): galleries built by the Romans after Julius Caesar's victory over the Helvetians to complete the defense system elaborated by Caesar during the Gallic wars.