Alt-Signau castle was the ancestral home of the Barons of Signau. The family was first mentioned in 1130 when Werner von Signau appeared in a historical record. The castle was designed to protect and control the road between the Emmental and the Aare river. In the mid-14th century the castle was abandoned when the family moved to Neu-Signau Castle on a hill across the valley.
The ruin is relatively well preserved.
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.