In a glacial valley holding two lakes deep in the Wicklow mountains, St Kevin founded a hermitage in the 6th century that grew into a monastic city. A thirty-metre round tower, a cathedral, the stone-roofed oratory called St Kevin's Kitchen and a graveyard of leaning slabs survive under the beeches. Trails climb from the upper lake to abandoned lead mines and a waterfall. Come before ten, when the coaches arrive.