The Brusselpoort is the sole remaining city gate of the original twelve gates of the city of Mechelen. This imposing structure dates from the 13th century. Because of its exceptional height, towering above the other gates, it was also called the 'Overste poort' (superior gate). In the 16th century, the towers were lowered and the roof construction was altered to the present configuration. In the course of the centuries, the building had many different uses from police station to youth center, from duty collector's office to artist's workshop.
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.