Radzyn Chelminski was the seat of the Teutonic Knights' Commandry. The castle is one of the oldest castles built by the Teutonic Knights, built in the 13th century. In 1446 the castle went into Polish control, in 1628 during wars with the Swedes the castle was partially devastated, slowly turning into a ruin.
Currently you are still able to see the tower - damaged by artillery fire. In 1780 Prussian authorities ordered to deconstruct whatever is let of the castle. Bricks from the three wings of the castle were used to build houses for the nearby community. The castle's deconstruction was stopped towards the end of the 19th century.
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.