The Château de Careil is a fortified house constructed from the end of the 14th century and enlarged in the 15th and 16th centuries. The manor had originally a defensive function, as witnessed by the crenellated curtain wall which still exists. Under the Reformation, it served as a place of worship for the protestants established in the Guérande peninsula. For this reason, it was attacked and pillaged on 11 May 1589 by the Catholic League. In 1699, some time after the Revocation of the Edict of Nantes, the manor was siezed and sold to a Catholic family. After becoming a restaurant in 1924, the site is currently a visitors' centre. A third wing of the building no longer exists; it was destroyed in an accidental fire in the 18th century.
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.