Killarney National Park, Killarney, County Kerry, Ireland (off the R562 Killorglin).

Hewn from solid rock by slow-moving ice over two million years ago, the 11km Gap of Dunloe is one of the finest examples of a glaciated valley in Western Europe. The narrow valley is located between Macgillycuddy’s Reeks and Purple Mountain and features five separate lakes, connected by the River Loe. The ‘Wishing Bridge’ between Coosan Lough and Black Lake is a popular tourist spot.