Its large size and occasional complexity make the cave a challenge for even experienced cavers.
The rest is open only to experienced cavers.
Upper Ribblesdale has long been a magnet for experienced cavers, potholers and geologists.
I was with four experienced cavers and one other first-timer.
Many other caves can be accessed with a permit by experienced cavers.
Many of them are experienced cavers who find unknown labyrinths a challenge.
Only experienced cavers are allowed access, and it is not open for the general public.
Instead, this is usually undertaken by other experienced cavers who undergo regular training through their organizations and are called up at need.
Thus, its membership draws experienced cavers, particularly those interested in cave surveying and cartography.
But even very experienced cavers had been killed.