The Vichtenstein castle sits above the Danube valley opposite to the market municipality of Upper Cell (Lower Bavaria). The castle is in the centre of the municipality Vichtenstein. There is no documentary for the construction of the castle but it is believed to have been started around the year 1100. The castle was an administrative centre of the Bishopric of Passau and in the 14th century it was mortgaged several times until it became the property of the counts of Schauberg.
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.