Glendalough

A glacial valley whose Irish name means the valley of two lakes, and the site of an Early Medieval monastic settlement founded in the sixth century by St Kevin, who came back with a small group of monks to found a house where the two rivers meet. He died around 618, and for the next six centuries the place flourished, the Irish Annals record the deaths of its abbots and the raids on it. Around 1042 oak from Glendalough built the second-longest Viking longship ever recorded, about thirty metres; a replica made in 2004 sits in Roskilde.