Mentioned by Lonely Planet Top Choices
Top things to do in Ireland
"Standing guard over Inishmore, Dun Aengus, 8km west of Kilronan, has three massive drystone walls that run right up to sheer drops to the ocean below. Believed to be up to 2000 years old, the fort is protected by remarkable chevaux de frise, fearsome and densely packed defensive limestone spikes. Displays at its small visitor centre provide context and a 900m walkway wanders uphill to the fort itself."