The Gothic Roupov castle was founded in the 13th century, and after a Renaissance modernization was one of the most beautiful Czech castles. The now completely standing part was built later and is being used by the current owners, the old ruined part hides many original architectural pieces, and is freely accesible. The original black kitchen with a medieval chimney is still present, and a gothique well. The castle was in usable state in the late 18th century, but slowly deteriorated, and the old part was disassembled for stone when a nearby village burned down and building material was needed. Some walls collapsed in 1817 and the castle became a ruin. Today the old part is conserved.
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.