Ogof Draenen

The cave was known only as a small entrance on a steep hillside, until several years of digging broke through into major passage development in October 1994. It was then explored at unprecedented speed to become the longest known cave in Wales. Water has been traced from locations within Ogof Draenen to a resurgence beside the Afon Lwyd at Pontnewynydd several kilometres to the south, where it is used as a supply by Welsh Water.