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.
Narikala is an ancient fortress overlooking Tbilisi, the capital of Georgia, and the Kura River. The fortress consists of two walled sections on a steep hill between the sulphur baths and the botanical gardens of Tbilisi. On the lower court there is the recently restored St Nicholas church. Newly built in 1996–1997, it replaces the original 13th-century church that was destroyed in a fire. The new church is of 'prescribed cross' type, having doors on three sides. The internal part of the church is decorated with the frescos showing scenes both from the Bible and history of Georgia.
The fortress was established in the 4th century and it was a Persian citadel. It was considerably expanded by the Umayyads in the 7th century and later, by king David the Builder (1089–1125). Most of extant fortifications date from the 16th and 17th centuries. In 1827, parts of the fortress were damaged by an earthquake and demolished.