In 25 km in the North, the Saône describes a wide meander and comes to pour at feet of the abrupt(steep) hillside of the tray(plateau) of Dombes. It is there, in the river, green and sunny site, that rises the city of Trévoux.At the beginning of the XII-th, Trévoux is mentioned as river and ground toll. The castle in the octagonal donjon, the surrounding wall(speaker) with one of its doors, the tower of the arsenal and the ancient district call back(remind) Trévoux's medieval origin. The political independence of Dombes's sovereign power in the margins of the realm, is at the origin of the development of Trévoux. A parliament in the remarkable ceiling paints, a printing office known in Europe of the XVIII-th century, an apothicairerie, a wireworks then an industry of the diamond field exporting in the world, testify still of this brilliance.