Have you ever seen a hexagonal cave? Fingal’s Cave, on the Scottish island of Staffa in the windswept Inner Hebrides, is one of the most unusual caves in the world. It is the only known cave which is formed completely out of hexagonally-jointed basalt, and features a walkway which is situated just above water level. The cave even inspired Felix Mendelssohn’s 19th Century masterpiece “Hebrides Overture”.