Since its founding, the city is protected behind its walls. The wall is exceptional because Vauban was doubled by superimposing two levels of covered parapets, unique feature in his work.
The vaulted traffic sheath of the lower level is based on the remains of the medieval walls, while the upper walkway is crowned with a traditional slate roof. Some medieval towers are still in place, included within the bastions of Vauban has adapted to the extreme lack of space and the proximity of the mountains...