Orkney has a stunning array of coastal scenery which is amongst the most impressive in the British Isles. The wonderful variety reflects the interaction of rock type, glaciation and sea level change in one of the highest energy marine environments in the world. The exposed rock coasts facing the Atlantic and the North Sea are faced by many kilometres of high cliffs, often highly indented by deep geos and penetrated by spectacular caves. Long sections of the coastline are fringed by extensive shore platforms. More sheltered shores carry softer forms, with extensive dune systems and broad, empty beaches. Change is evident everywhere, with cliff falls and the progressive erosion and destruction of archaeological sites in bay heads, a reflection of the energy of the coastal environment and of continuing sea level rise.