Turku castle is a national monument and one the most remarkable medieval castles in Finland. It's also one of the largest existing castles in Scandinavia. A history of Turku castle begins from the year 1280. The Swedish conquerors of Finland intended it originally as a military fortress.
During 15th and 16th centuries its defences were strengthened and living quarters were added. The castle served as a bastion and administrative centre in Finland. It was also a residence for kings of Sweden, when they visited in Finland. During the struggles for power of Sweden in 14th and 15th centuries Turku castle was several times under siege. Probably the longest one occured in 1364-65, when German lord Albrecht von Mecklenburg besieged it over eight months before Swedish troops surrounded.
The heyday of Turku Castle was in 1556-1563, when King John III of Sweden lived there. During this castle was enhanced to Renaissance fashioned living palace. John III married Polish princess Catherine Jagellon who also lived in Turku short period in 1562-1563. In 1614, when King Gustav II Adolf visited the castle, a tremendous fire destroyed the wooden structure of the main castle almost completely. After this the main castle was abandoned and used partly as a store, partly just stood empty. In the 19th century castle was used as a prison. The last accident beset the castle in the summer of 1941 soon after the Continuation War had begun when an incendiary bomb hit the main castle.
Today Turku castle is Finland's most visited museum, with attendance reaching 200,000 in some years. In addition, many of the larger rooms are used for municipal functions.
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.