Fjell fortress was built by the German occupation forces during the Second World War. The construction works were commenced late summer 1942, and completed so far that they could fire the main gun for the first time as early as in June–July 1943. The fort was a significant link in the coastal defence of Norway.
The main gun was also to a certain extent employed in the interception of foreign aircraft raids against Bergen.The fortress has areas over and under the ground, with a network of tunnels two miles long on the surface and in the mountains.
The fortress area is today the property of the Norwegian Armed Forces, while Sotra og Øygarden Forsvarsforening (Sotra and Øygarden Defence Association) are responsible for conducting the preservation and maintenance.
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.