The traditional legend of the witch who lived in Somerset's Wookey Hole Caves, never fails to grip visitors' imaginations. On my visit, a group of 11-year-olds from Bloomfield Road primary school, Bangor, County Down, are listening to guide Steve Robinson's engaging mix of humour and educational fact.
The witch, they are told, was turned to stone by a monk who loved fried food - called Chip-munk. He sprinkled her with water and she was petrified "in a silent, toothless scream of horror", while her dog was transformed . . . into a "rockweiler".
Giggles punctuate his commentary as he points out St Michael's Mount, Michael Jackson and Casper the friendly ghost, and warns everyone to watch their feet on the slippery rocks: "But if you do fall, take a moment to look at a spectacular calcite formation on your right."
Meanwhile, he is conveying how remarkable it is that all the wonders in the Witch's Kitchen and Parlour and other subterranean chambers have been carved out by the River Axe over a million years.
They see how dissolved limestone has reformed into dripping stalactites, how even tiny straw ones, a couple of inches long, have taken 350 years to form, and how great stalagmites have built up over a billion years by the same process as scale in a kettle. They gaze at the kaleidoscope of colours embedded in the pale limestone - reddish-brown iron oxide, black manganese, golden ochre, and grey from the lead once mined on the Mendip Hills.
Standing in the 100-foot high Great Cavern where the cold, green waters of the Axe flow 70-feet deep, they learn that the theory that the cave had been formed by a swirling torrent of water was proved in the Sixties when it flooded and the water turned into a whirlpool. It was because of the Axe's pure and plentiful water that a thriving papermaking industry grew up at Wookey Hole. School groups can now see a film, The Great Paper Chase, featuring the ghost of William Hodgkinson, who bought the papermill in 1855. It traces the history of paper, its importance to daily life, and 400 years of making legal documents and watermarked banknotes at the mill.
After a period of decline, it was purchased by Madame Tussaud's in 1976, and is now one of only two handmade paper mills in Britain, exporting worldwide. The film shows the vatman judging the quality of the cotton rag mixture known as "stuff", and dipping and shaking the wooden mould on which it forms into paper.
He works in rhythm with the coucher who lays each sheet down on a thick piece of woollen felt. Children can also become vatmen and couchers themselves.
One pupil, Garth, says: "It feels like wet paste full of tissues. The hardest part is swishing it around until the fluid has drained away." Visits usually end with the Victorian fairground and arcade, and the magical mirror maze where more than 40 mirrors create the impression of a huge, colourful crypt.
John Besant, the teacher in charge of Bloomfield Road school, has been bringing groups here for over 20 years. A light-hearted holiday atmosphere prevails as "these pupils have done all their exams and will just do a general workbook when they get back," he says.
But for other recent visitors, Wookey Hole forms the focus of several weeks' work. Carol Jones, for example, brings 10 and 11-year-olds from the Wells Cathedral junior school as part of their geography and history programme on the Mendips.
"After previously visiting the source of the Axe, they follow its course through the caves, and its exit, and study the caving system and limestone features. We discuss how water wears its way through rock or sits on the surface, its availability and importance for such industries as papermaking, and how it must be caught in the right place so it is pure," she says.
Shirley Gibbs, of St Mary's school, Beaminster, Dorset, said the visit with her key stage 1 class "fitted well into our topic for the term which is 'Colour and Light'.
"The children followed up with writing, pictures and dark and light poems, which led on to the theme of evil and good. We made a dark, Wookey Hole cave in the classroom which they enter with torches. The mirror maze led to reflection, refraction and light experiments. We will definitely go again," she says.
A 20-minute video, 'Windows into Darkness', is available on free loan, as well as a free teachers' guide with 12 activity sheets for junior and secondary pupils. School group rate: Pounds 2.50 per pupil.
For further details, contact: Wookey Hole Caves, Wells, Somerset BA5 1BB.
Tel: 01749 672243