Glastonbury Tor Since the alleged discovery of Arthur and Guinevere's remains in the 12th century, it has been claimed that Glastonbury Tor stands on the site of ancient Avalon, the island where Arthur died following his final battle against Mordred. Once surrounded by marshland, Glastonbury Tor was virtually an island during the Dark Ages.
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)