1 Best Sight in The Northern Highlands and the Western Isles, Scotland

This atmospheric cavern, hollowed out of the limestone by rushing water, feels like something from a fantasy novel. Located a mile east of Durness, the combined sea-and-freshwater cave, complete with gushing waterfall, can be reached via a steep cliff stairway from the Smoo Cave parking lot. But don't start your descent before reading the explanatory boards at the top of the stairs: they tell the history of those who lived and used the caves in much earlier times. From April through October, 20-minute boat trips (£10) into the cave's inner chamber are available. Once you've climbed back up to the parking area, cross the road for a view down into the cavern from atop the waterfall.