Peel Castle was originally constructed by Vikings. The castle stands on St Patrick's Isle which is connected to the town by a causeway. It is open to visitors during the summer.
The castle was built in the 11th century by the Vikings, under the rule of King Magnus Barefoot. While there were older stone Celtic monastic buildings on the island, the first Viking fortifications were built of wood. The prominent round tower was originally part of the Celtic monastery, but had battlements added at a later date. In the early 14th century, the majority of the walls and towers were built primarily from local red sandstone, which is found abundantly in the area. After the rule of the Vikings, the castle continued to be used by the Church due to the cathedral built there – the see of the diocese of Sodor and Man – but was eventually abandoned in the 18th century.
The castle remained fortified, and new defensive positions were added as late as 1860. The buildings within the castle are now mostly ruined, but the outer walls remain intact. Excavations in 1982-87 revealed an extensive graveyard as well as the remains of Magnus Barefoot's original wooden fort. The most spectacular finds were the 10th century grave of 'The Pagan Lady' which included a fine example of a Viking necklace and a cache of silver coins dating from about 1030. The Castle's most famous 'resident' is the so-called Moddey Dhoo or 'Black Dog' ghost.
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.