The remains of the Castle can be visited
Peel Castle

On the small St. Patrick's Isle, connected to the town of Peel by a causeway, is Peel Castle, a castle ruin on the Isle of Man. Originally built by Vikings, the complex is today a testament to bygone eras.
History+
The origins of Peel Castle date back to the 11th century, when Vikings under King Magnus Barefoot erected the first fortifications here. Although older Celtic monastic stone buildings already existed, the initial Viking structures were made of wood. The round tower was originally part of the Celtic monastery and later had battlements added. In the early 14th century, most of the walls and towers were built primarily from the abundant local red sandstone. After the Viking era, the castle continued to be used for ecclesiastical purposes due to a cathedral located there, but was eventually abandoned in the 18th century.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://en.wikipedia.org/wiki/File:Isle_of_Man_Peel_Castle.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 54.2263, -4.6993