Uenglingen gate was built ca. 1450-1460 and is regarded to be amongst the finest late medieval city gates amongst those built in the northern German brick Gothic style, only surpassed by the Holsten Gate in Lübeck. The gate is believed to have been built by Stefan Boxthude, one of the most reknowned masterbuilders of the 15th century. The gate's tower, boasting sheer rounded ramparts, was originally the main gate of larger defensive fortifications that also included a foregate and a ward (a courtyard enclosed by a circular wall).
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.