This Vauban citadel, built between 1668-1672, is nicknamed "the useless beauty" (la belle inutile), due to the fact it was not of much use, at least not for protecting the city from Spanish troops, but was rather only ever used to keep tabs on the townsfolk. In July 2008, the citadel became a UNESCO World Heritage Site and is one of the 12 major fortifications Vauban built in France.