Grolman Bastion was part of the Königsberg fortification system. Named after General Karl Wilhelm von Grolman, it was finished in 1851. It was strengthened with casemates and caponniers inside its wall and consists of lesser Oberteich and Kupferteich Bastions. The Bastion was considerably damaged by Soviet Army in the World War II. There was a vegetable storehouse in the Bastion during the Soviet time. Nowadays this fortress memorial is under reconstruction.
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.