Fingal's Cave on Staffa - Its struture is unique. Nowhere else is there a sea-cave formed completely in hexagonally-jointed basalt. To this the size, the sounds, the colours, and the remarkable symmetry of this 227-foot cavern; and by Nature's gift of fractured columns forming a crude walkway just above high-water level, allowing exploring visitors to go far inside.
Fingal’s Cave, Inner Hebrides, Scotland. "Fingal's Cave is a sea cave on the uninhabited island of Staffa, in the Inner Hebrides of Scotland, part of a National Nature Reserve owned by the National Trust for Scotland" via Wikipedia.