Aillwee Cave is a show cave in the hillside south of Ballyvaughan, more than a kilometre of passages leading into the heart of the mountain, with an underground river, a waterfall, and stalactites and stalagmites. The bones of brown bears have been found inside, and it may have been one of the last bear dens in Ireland.
The cave is privately owned and run together with a birds of prey centre as the Aillwee Cave and Birds of Prey Centre. The formations you see are rarely more than 8,000 years old, but calcite deep in the cave has been dated to more than 350,000 years.