Dan-yr-Ogof Caves
Dan-yr-Ogof in the Swansea Valley of the Brecon Beacons National Park is the largest and most complex showcave system in Britain, a labyrinth of passages and caverns discovered in 1912 and progressively explored over the following century that extends for approximately seventeen kilometres of surveyed passages beneath the limestone country of the upper Swansea Valley. The showcave complex open to visitors includes three separate cave experiences of considerable variety, from the spectacular stalagmite formations of the Cathedral Cave to the archaeological Cathedral Cave with its Iron Age and Bronze Age deposits.
The Cathedral Cave takes its name from the enormous cavern at its heart, a chamber of approximately 40 metres height filled with the largest single collection of stalagmite and stalactite formations of any showcave in Britain, assembled over hundreds of thousands of years by the dripping water that has carved and decorated the cave since the limestone was first penetrated by surface water. The scale of the individual formations, some of considerable height and girth, creates an atmosphere of geological majesty that justifies the cave's name.
The Bone Cave, the third showcave in the complex, contains the archaeological evidence of the human occupation of the cave system from the Bronze Age to the Roman period, including human skeletal remains of at least forty-two individuals deposited in the cave over a period of several thousand years. The Dan-yr-Ogof complex also includes an extensive dinosaur park in the surface grounds that provides entertainment for younger visitors while the archaeological and geological interest of the caves appeals to adults.