The one-time home of the O’Brien clan is now an immense ruin. Standing at the edge of the vast limestone plateau known as the Burren, a crumbling four-story 17th-century mansion and a five-storey tower of 1480 are all that’s left of the stronghold. The castle’s gate is now at Dromoland Castle. Famous residents have included Máire Rua, who married four times to protect the lands, once to an officer in Cromwell’s army, even though her previous husband had been killed fighting it.