Karjohansvern was the main base for the Royal Norwegian Navy from 1819 to 1963. It was the site of the Navy Main Yard, Navy Air Plane Factory, Navy Museum, Navy Schools and the forts Norske Løve andCitadellet.
Naval District East (ØSD) based there was disbanded in 2002. The Museum, the Royal Norwegian Navy Band, a department of theNorwegian Defence Research Establishment and some of the Navy's school administration is still present. As of 2006 the entire base including 73 buildings has been given protected heritage status by the Directorate for Cultural Heritage in Norway. Karljohansvern is open to the public. Only Vealøs is still owned by the Department of Defence.
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.