Araburg castle was built in the 12th century and continues to expand into the 17th century. During the first Turkish siege of 1529 it was a refuge place for the local population. Araburg also played a role in the religious wars between Catholics and Protestants. In 1683 it was destroyed during the second Turkish siege. Since then Araburg has been ruined.
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.