The limestone plateau of the southern Fforest Fawr, around the upper reaches of the River Tawe, is riddled with some of the largest and most complex cave systems in Britain. Most can only be visited by experienced cavers, but the National Showcaves Centre for Wales is a set of three caves that are well lit, spacious and easily accessible, even to children.
The highlight of the 1.5-mile self-guided tour is the Cathedral Cave , a high-domed chamber with a lake fed by two waterfalls that pour from openings in the rock. Nearby is the Bone Cave , where 42 Bronze Age skeletons were discovered. Dan-yr-Ogof Cave , part of a 10-mile complex, has interesting limestone formations.
The admission fee also gives entry to various other attractions on-site, including a museum, a reconstructed Iron Age farm, a prehistoric theme park filled with life-sized fibreglass dinosaurs, a shire-horse centre and a children's playground. The complex is just off the A4067 north of Abercraf.
Beneath the hillside to the east lies the twisting maze of subterranean chambers known as Ogof Ffynnon Ddu (Cave of the Black Spring), the deepest and third-longest cave system in the UK (308m deep, with 30 miles of passages). This one is for expert potholers only, but you can explore it virtually at www.ogof.net.
