Hidden Realms by Martyn Farr showcases 100 of the most outstanding caves, potholes and mines across the UK and Ireland.

Martyn is one of the world’s most respected cavers, and he has been at the forefront of cave exploration in the UK and further afield for decades. Throughout Hidden Realms he combines his experience and passion for caving to present his favourite subterranean sites – the best of the best in the UK and Ireland. This is an explorer’s-eye view of the most secret and wild places in the British Isles.

Many of the most highly rated and classic caves and mines are here – Gaping Gill with its almighty chasm and Porth yr Ogof with the swirling waters of White Horse Pool. Also captured are more remote, difficult-to-explore and seldom-visited places – including the challenging-to-reach bivvy site known as Restaurant at the End of the Universe in Ogof Daren Cilau and Circus Maximus in Ogof Draenen. For pure, pristine displays of formations the wonders of Neverland in Upper Flood Swallet cannot be surpassed. Here, too, there are a wide range of mines, today mostly abandoned and silent. Some, such as Nenthead, contain important and intriguing industrial archaeology. Others offer an underground adventure for intrepid explorers: the Tyrolean crossings and bridges of the Croesor–Rhosydd Slate Mine or the thrilling challenges of Cwmorthin Slate Mine which will test the nerve of all comers.

Venture into the world of caving – at its spectacular, mysterious and inspirational best. Martyn’s stunning photographs capture moments held in time that most people have never seen, and the accompanying texts skilfully weave nuggets about the history of the sites hidden beneath us.

We don’t yet know how many more caves and tunnels there are waiting to be explored. Some may be the hardest places in Britain and Ireland to reach, yet enormous scope remains for discovery and original exploration. For most, this is undoubtedly an unknown realm. Within these pages, underground wonders are presented to the wider world to fire the imagination.