Jever castle dates back to a weir from the late 14th century. The fortress got its typical characteristics mostly from the massive keep, which during the 15th and 16th century was surrounded by a Vierseitanlage. When Jever became part of the Duchy of Oldenburg in 1818, the castle was declared an auxiliary residence of the Dukes of Oldenburg and the now useless outbuildings and fortification were done away with. The museum has been situated in the castle since 1921 and features collections of cultural history, folklore and the archaeology of the Jever region.
The historic rooms also give an overview of the lifestyle of the 16th to 19th century. You will have the best view from the 67 meter-high castle tower. The viewing platform offers a unique view over the expanse of the Friesian coast.
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.