Porth Yr Ogof

Porth yr Ogof is a cave located near the village of Ystradfellte, near the southern boundary of the Brecon Beacons National Park in Wales. In 1998 the cave's passageways had been measured as over 2.25 km in length. Among the cave's fifteen entrances is the largest cave entrance in Wales (but many of those entrances are only accessible to cave divers). The cave was used as a show cave many years ago, but it does not have the attractions of more decorated caves such as Dan yr Ogof, and so today the cave is more often used to introduce people to the enjoyment of the exploration of caves.