Three spectacular prehistoric forts stand guard over Inishmór, each believed to be around 2000 years old. Chief among them is Dún Aengus, with three massive drystone walls that run right up to sheer drops to the ocean below. The fort is protected by remarkable chevaux de frise, fearsome and densely packed defensive limestone spikes. A small visitor centre has displays that put everything in context and a slightly strenuous 900m walkway wanders uphill to the fort itself. Dún Aengus is around 7km west of Kilronan.
Powerful swells pound the 60m-high cliff face. A complete lack of railings or other modern additions that would spoil this incredible site means that you can not only go right up to the cliff's edge but also potentially fall to your doom below, so take care.
