All that remains of the ancient medieval bridge of Romagnano Sesia, which once united the shores of Romagnano and Gattinara, crossing the waters of the great River Sesia, are the three isolated arches that rise  in a green park far from the river, the bed of which was altered in 1655 to protect the town centre from the dangers of the waters in full spate. The three arches, defined by popular tradition as “the gates of sin” or “the gates of the Devil” have an uncertain date. Made from small river pebbles  in a herring-bone pattern, they tilt towards the right river bank though remaining perpendicular to the previous course of the river. Probably the bridge was not constructed to link the closest points of the opposite banks, but rather following a particular line that permitted the foundations to be built on bare rock, a theory which would seem to be confirmed by the fact that the dimensions of the arches are of different sizes. The bridge was destroyed in 1223 according to the peace treaty between Novara and Vercelli: the remains of the structure are however still surprising for its ingenious architectural construction.