Located in the eastern Pyrenees at an altitude of 1600 metres, the stronghold of Mont-Louis was built from scratch by Vauban on granite terrain and is perfectly adapted to the geography of the site. Work started in 1679 and was completed in two years. The fortified ensemble was added as a complement to Villefranche-de-Conflent in securing the route from the Pyrenees.
This ensemble consists of two square structures, in tiers on the slope: a citadel with orillon bastions and demi-lunes (ravelins) and a new town enclosed in the enceinte. Although it is rare, all the watch towers and drawbridge gates as well as both churches and wells have been preserved intact since the 17th century. The citadel is still used for military purposes today.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.