The citadel of Lille is a bastioned fortress built between 1668 and 1671, designed by the famous French fortress architect Vauban. It is one of Vauban's most notable fortresses. Here you can see the entrance to the barracks Boufflers. At the gate, the symbol of the "Sun King" Louis XIV can be seen. At that time the barracks were still used by the army. Today, it is the headquarter of the Rapid Reaction Corps – France.