The ruins of the Pajrek Castle (Burg Bayereck) lie above the town of Nýrsko in the western part of the Bohemian Forest at a height of 505 metres above sea level.
This important border castle was built at the beginning of the 14th century, but by 1472 it had already been abandoned. In 1504, the castle was rebuilt, but it was only used until the middle of the 16th century, when it was finally abandoned. Only the remains of the huge tower have survived.
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.