This impressive system of caves and tunnels, 3km east of Discovery Bay, extends for about 45km. The steps lead down into the impressive chambers, where statuesque dripstone formations are illuminated by floodlights. The Taíno people left petroglyphs carved into the walls; the caves have frequently been used as hideouts – by the Spanish during the English takeover of the island in 1655, by runaway slaves in the 18th century, and between the two world wars by smugglers running arms to Cuba. The highlight is Green Grotto, a glistening subterranean lake 36m down. The entrance fee includes a guided one-hour tour, which is particularly family friendly. The guides conduct their tours with humor and attempt to amaze you by tapping stalactites to produce hollow drum-like sounds, as well as pointing out the different species of bat that live in the cave, and their imported predator, the Jamaican yellow boa.