Sobowidz Castle was built in the second half of 14th century by the Teutonic Order. During the Polish–Lithuanian–Teutonic War it was conquered by Polish, but later returned to Teutonic Order. The castle was mainly destroyed in 1454 when Teutonic Knights surrended. In the 16th century the castle was rebuilt to Governor palace, but it was again destroyed by Swedish army in the 17th century and demolished in 19th century. The current red-brick building was built after that. Today Gothic basement, moat and parts of the wall remain of medieval castle.
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.