Füssen's landmark, the Hohes Schloss (high castle), sits on a high rock and overlooks the village. Hohes Schloss is one of Bavaria's largest and best-preserved Gothic castle complexes, and is the former summer residence and fortress of the prince bishops of Augsburg.
The first castle on the hill dates back to the age of Roman Empire. The current castle was built in the 13-15th century. It was already integrated to city fortifications in 1363 and largely extended and renovated by bishop Friedrich II in the late 1400s and again around 1680 by Prince Bishop Johann Christoph von Freyberg.
The north wing of the palace contains the Staatsgalerie (State Gallery), with regional paintings and sculpture from the 15th and 16th centuries. The Städtische Gemäldegalerie (City Paintings Gallery) below is a showcase of 19th-century artists.
The inner courtyard is a masterpiece of illusionary architecture dating back to 1499.
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.