Stegeholm's Castle Ruin is located on Slottsholmen by the mouth of Gamlebyviken. The oldest notes about Stegeholms castle are from the 14th century. It was probably built before 1370 by Albert II, Duke of Mecklenburg (the father of King Albert of Sweden). The castle was destroyed by fire in 1517 and rebuilt in 1521. In 1612 it was conquered by Danish. The final destruction appeared in 1677 when Stegeholm was destroyed by Danish-Dutch fleet. Today Västerviks Visfestival (Song festival) is organized in the castle ruins annually.
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.