Citadel of Lille
Vauban [Lille">Sébastien Le Prestre de Vauban">Vauban [Lille Boufflers.jpg|thumb|]
The Citadel of Lille is a pentagonal citadel of the city wall of Lille, in France. It was built between 1667 and 1670. It hosts the Corps de réaction rapide France.
Dubbed "Queen of the citadels" by Vauban, it is one of the most notable citadels designed by Vauban. It is remarkable for its size, the quality of the architecture, and the state of preservation today. Its various components have been classified as historic monuments in 1914, 1921 and 1934 respectively.
A first-class military installation
Image:Grondplan [citadel Lille.JPG|thumb|left|Layout of the citadel]Image:MoutonSoaySoaySheepUrbanGrazing2012LilleCitadelleLamiotF 06.jpg|thumb|Soay sheep used by the city to crop vegetation around the fortifications. These small sheep are very comfortable on the slopes and replace the mechanical equipment otherwise required.
This "Queen of Citadels" is the matrix of most citadels designed by Vauban. Established on the border of Flanders, it was part of a double-line of fortified towns between Gravelines, Dunkirk and Maubeuge-Rocroi. It delineated the famous "Pré Carré" conceived by Vauban comprising 28 fortified cities. From Lille, Vauban supervised the construction of the many citadels and canals of the North, which controlled the border between France and Belgium.
Lille was taken from Spain by French troops in August 1667, and Louis XIV immediately ordered the construction of a fortress. Louis Nicolas de Clerville and Vauban proposed plans. Vauban's were those chosen by the King. Work was started in 1668 under the direction of Lille's master mason, Simon Vollant. In 1671, the citadel became operational while Vauban continued to shape the city by constructing, a few steps away, a new neighborhood around the Rue Royale. The design of the citadel follows a simple but very effective idea: not one of its walls can be approached by the enemy without them being under fire from a nearby wall.