The Pont au Double is a single span, cast iron arch bridge that spans between the Left Bank and the Ile De la Cite next to Notre Dame Cathedral. A bridge has stood at this site since 1634. The current bridge was built in 1883. It is 45 m (148 ft) long and 20 m (66 ft) wide. Its unusual name comes from the toll (a double denier) that was required to cross the earlier bridge.