GAPING GILL is one of the great wonders of Yorkshire, a 332ft deep pothole that only a few brave souls ever venture into.
It is a landmark on the slopes of Ingleborough into which gushes a stream, Fell Beck.
After falling through one of the largest known underground chambers in Britain, the water disappears into the bouldery floor and eventually resurges adjacent to Ingleborough Cave.
Only experienced pothole explorers usually get to view this monument to nature but yesterday a few hardy souls were guided into the shaft.
The Bradford Pothole Club has held a ‘Winch Meet’ here for over 60 years, allowing members of the public and non-cavers the chance to visit this truly awe-inspiring underground scene.
It is an experience never forgotten and many visitors return year after year, becoming familiar faces to be welcomed back as old friends.
The cavern is floodlit, allowing the public and cavers alike a view not normally seen outside Winch Meets. It also enables members of the public to meet cavers and discover that they are surprisingly normal people with just a wild enthusiasm for all places underground.
The Gaping Gill system is one of Britain’s longest and most complex cave systems.
As well as the Main Shaft the system has nineteen other entrances. All these entrances unite underground and the water running through the caves eventually emerges into daylight at Ingleborough Cave, the Show Cave passed on the walk up to Gaping Gill.
The connection between the two caves was made in 1983 by cave divers negotiating flooded sections of passages called sumps, using breathing apparatus.
The other entrances are not suitable for inexperienced cavers.
Gaping Gill - sometimes known as Gaping Ghyll - was the deepest known in Britain until Titan in Derbyshire was discovered in 1999.
Gaping Gill still retains the records for the tallest unbroken waterfall in England and the largest underground chamber naturally open to the surface.
Due to the number of entrances which connect into the cave, many different routes - with poetic names - through and around the system are possible.
Entrances include Jib Tunnel, Disappointment Pot, Stream Passage Pot, Bar Pot, Hensler’s Pot, Corky’s Pot, Rat Hole, and Flood Entrance Pot.
The Bradford Pothole Club, usually around Whitsun May Bank Holiday, and the Craven Pothole Club, around August Bank Holiday, each set up a winch above the shaft to provide a ride to the bottom and back out again for any member of the public who pays a fee.
A detailed 3D model of the chamber has been created using an industrial laser rangefinder which showed that its volume is comparable to the size of York Minster.
The first recorded attempted descent was by John Birkbeck in 1842 who reached a ledge 180ft down the shaft which bears his name. He has been lowered down by farm labourers.
The first complete descent was achieved by Édouard-Alfred Martel in 1895 using a rope ladder and a candle.
He kept in contact with people on the surface the surface by telephone.
In 1983 members of the Cave Diving Group made the underwater connection into Ingleborough Cave.
An extreme rock-climb is possible up the main shaft which requires very dry conditions.
• The winch meet is today, Wednesday and Thursday, 8am to 5pm, and on Friday, 8am to 1pm. The cost is £15. First come, first dropped.