Besançon's Vauban citadel has been listed as a UNESCO World Heritage Site. Louis XIV of France conquered the city for the first time in 1668, but the Treaty of Aix-la-Chapelle returned it to Spain within a matter of months. While it was in French hands, the famed military engineer Vauban visited the city and drew up plans for its fortification. The Spaniards built the main centre point of the city's defences, 'la Citadelle', siting it on Mont Saint-Étienne, which closes the neck of the oxbow that is the site of the original town. In their construction, the Spaniards followed Vauban's designs.
In 1674, French troops recaptured the city, which the Treaty of Nijmegen (1678) then awarded to France. As a result of control passing to France, Vauban returned to working on the citadel's fortifications, and those of the city. This process lasted until 1711, some 30 years, and the walls built then surround the city. Between the train station and the central city there is a complex moat system that now serves road traffic. Numerous forts, some of which date back to that time and that incorporate Vauban's designs elements sit on the six hills that surround the city: Fort de Trois Châtels, Fort Chaudanne, Fort du Petit Chaudanne, Fort Griffon, Fort des Justices, Fort de Beauregard and Fort de Brégille. The citadel itself has two dry moats, with an outer and inner court. In the evenings, the illuminated Citadelle stands above the city as a landmark and a testament to Vauban's genius as a military engineer.
The Citadel is built on top of a large syncline on a rectangular field crossed across its width by three successive bastions (enclosures, or fronts) behind which extend three plazas. The whole is surrounded by walls covered by circular paths and punctuated by watchtowers and sentry posts. The walls are up to 15 to 20 metres high with a thickness between 5 and 6 metres.
References:The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.