To the south of Lower Lough Erne lies a limestone plateau, where Fermanagh's abundant rainwater has carved out a network of subterranean caverns. The largest of these are the star attraction of the Marble Arch Caves Global Geopark. Popular 1¼-hour tours feature spectacular chambers and underwater rivers. The caves are 16km southwest of Enniskillen, and 4km west of Florence Court, reached via the A4 and the A32. Book tours in advance in summer.