Dún Aonghasa is an ancient circle fort built on Inis Mór, the largest of the Aran Islands. It was probably a complete enclosure at one point, but the cliffs have eroded and collapsed with part of the fort into the sea.
The cliffs are about 280-300 feet high above the sea and look upon the Irish coast on a clear day, which may have contributed to the choice of location. The site was first enclosed with a more primitive stone wall about 1100 BC, and ultimately it had four concentric stone walls of startling engineering, encompassing about 14 acres of protected area. It also featured a cheval de frise between the third and fourth walls, a field of deliberately placed upright stones meant to seriously impede any charge by an enemy force.
Continue reading