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 Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.