A huge cave system beneath the slopes of Ingleborough in the Yorkshire Dales is accessible to the public this weekend.
Gaping Gill is Yorkshire's largest underground chamber and is so big that York Minster could fit inside it.
Every May and August Bank Holiday weekend, local caving clubs set up a winch enabling ordinary members of the public to descend the 360ft shaft into a hidden world usually only seen by experienced potholers.
Gaping Gill is a huge pothole on the southern side of Ingleborough that is fed by a stream called the Fell Beck, which re-emerges at Ingleborough Cave. It was once the deepest shaft in Britain until the discovery of Titan in the Peak District in 1999. Gaping Gill still has the highest waterfall in England - it's higher that Niagara Falls - and is the largest chamber that's open to the surface.
French caver Edouard-Alfred Martel was the first person to complete a descent of the cavern in 1895, using just a candle and a rope ladder. A local explorer from Settle called John Birkbeck had attempted the feat in 1842, but only made it 180ft down before his rope began to fray.
Nowadays, the winch machinery is open twice a year and members of the public can be taken to the bottom, where the Fell Beck is temporarily diverted by a dam and floodlights are erected to enable people to explore the chamber.
It takes about a minute to reach the bottom and the experience isn't ideal for the faint-hearted. Before the cave system was explored, local people thought it was a bottomless pit that led to Hell.
Bradford Caving Club are operating the winch from Saturday May 25 until Friday May 31 to coincide with the half-term holiday.
Here's all you need to know about using the winch
- It costs £15 per person to be winched down Gaping Gill
- The winch is operational from 8am until 5pm, but could close earlier if there is high demand
- You can't pre-book, but will be issued with a numbered tag on arrival
- You need to wear warm, waterproof clothing, clothes and sturdy footwear. Helmets are provided
- If you arrive via the Nature Trail there is a charge to pass through Ingleborough Cave - which is a separate attraction - of £1 per adult and 50p per child
- There are no public toilets available beyond Clapham village car park and there is only a basic 'field latrine' at Gaping Gill. The walk from Clapham to Gaping Gill can take between one and a half and two hours
- No food and drink is provided at Gaping Gill but refreshments are sold at Ingleborough Cave
- If the winch has reached its capacity for the day a notice will be posted at Ingleborough Cave
- Nobody weighing more than 20 stone (125kg) can use the winch
- Visitors are advised to bring a torch. Cameras are permitted
- Children aged six and above can use the winch if accompanied by an adult
- No members of the public are permitted to camp at Gaping Gill
- If arriving in a group, it cannot exceed 10 people
- Competent cavers with suitable equipment and experience may access the chamber using alternative entrances, but must sign in on arrival
- No dogs are allowed