Wik Castle is one of the best preserved medieval castles in Sweden. The first owner was Israel And in the end of 13th century. The current magnificent castle with seven floors was built in the late 15th century. The massive walls and moats made the stronghold impregnable. During the Middle Ages, the castle was one of the sturdiest strongholds in the Mälaren Valley, and Gustav Wasa once besieged Wik Castle for over a year without ever managing to get inside the walls. It was modified to the present French-style appearance in the 17th century.
Wik Castle has been owned by several noble families like Sparre, Bielke, Horn von Liewe, de Geer and von Essen. Today it is owned by the county council of Uppsala and used primarily for the council's own conference activities. It is at present closed to the public.
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.