St Nectan's Glen, Tintagel, Cornwall. One of Cornwall’s most sacred sites, St. Nectan’s waterfall is in a designated Site of Special Scientific Interest (SSSI). It has been described as amongst the ten most important spiritual sites in the country. A place of outstanding natural beauty. The magic and tranquility of St. Nectan’s Kieve are unique. The Kieve is a potent symbol of Mother Earth.