Vast sea cave with inner waterfall.
Smoo Cave, near Durness, has the largest sea-cave entrance in Britain — a vast limestone mouth you walk straight into down a flight of steps. Inside, the Allt Smoo burn tumbles twenty metres through a hole in the roof into a hidden chamber, half the cave carved by the sea and half dissolved out by fresh water. The main chamber is free to visit; a small boat tour reaches the inner chambers in summer, water levels allowing.
