One of the deepest and longest ravines in the Alps, the Liechtensteinklamm is off the beaten track but well worth the detour. The jaw-dropping chasm was carved out during the last Ice Age and takes its name from Johann II, Prince of Liechtenstein, who poured plenty of money into making the gorge accessible in the 19th century. Following raging waters flanked by vertical 300m-high cliffs, the footpath crosses bridges and passes through tunnels gouged into slate cliffs veined with white granite. The mossy boulders and crags glisten with spray from the water, which is at its most striking in the late afternoon when the sunlight turns it opal blue. The trail culminates at a spectacular 50m waterfall. Allow at least an hour to walk the gorge.