The world's best swimming pools (Condé Nast Traveller) - A huge rock pool on Treyarnon Bay, near Padstow in Cornwall, forms a natural swimming pool once the tide has gone out - several degrees warmer than a dip in the sea.
The Minack Theatre is an open-air theatre, constructed above a gully with a rocky granite outcrop jutting into the sea. The theatre is at Porthcurno, 4 miles from Land’s End in Cornwall, England. http://www.buzzfeed.com/hilarywardle/12-places-youd-never-believe-were-in-the-uk-aplm
Nanjizal beach, Cornwall, England This cave is known as the 'Song of the Sea'.' It lies on the East side of Nanjizal beach and has this spectacular pool at low water. Nanjizal lies half way between Porthcurno (Minack theatre) and Land's End in Cornwall. It can be only be reached by minimum of 20 minute walk.