The strategic importance of the mountain crest across from Ehrenberg has been known for a long time. In 1632 the Swedes marched to the gates of Ehrenberg. Only years later, from 1639 to 1645, under the Tyrolean regent Archduchess Claudia Fort Claudia was built, and named after this princess. In 1703 Fort Claudia was taken by the Bavarians, who began the occupation of Ehrenberg from here. In 1782 the fortress was closed down. Even in the 19th century, the old fortress was inhabited, yet was left to decay after it was abandoned.
In 2014, the world's longest pedestrian suspension bridge was completed between the Ehrenberg Castle ruins and Fort Claudia, spanning the strategically important pass that these two structures were in part meant to guard. The length of the bridge 403 meters, with a height 110 meters.
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.