The Burgkirche ('castle church') is one of the largest and most imposing fortified churches in western Germany. The church is surrounded by a cemetery, which is surrounded by walls. The Romanesque tower of the church with Gothic battlements and turrets is the oldest part of the church, which was built in several phases in the late Gothic period. The restored stained glass windows and paintings in vaults - both from the 15th century - are worth of seeing. The church served as a graveyard of local nobility and has lots of interesting tombs.
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.