Roche Rock, Cornwall by SharpeImages.co.uk, via Flickr. Partly carved out of, and partly created of the surrounding rock it is thought to have been either a hermitage and/or occupied by a leper. It also features in the story of Tristan and Isolde in the King Arthur legends.
Tintagel Castle in Cornwall is steeped in legend and mystery; said to be the birthplace of King Arthur. The castle also features in the tale of Tristan and Isolde and has a history stretching as far back as the Romans. (http://www.english-heritage.org.uk)