They’ve spent the last five decades going underground.
Now, however, members of the West Yorkshire-based Northern Cave Club (NCC) are preparing to celebrate its 50th anniversary with a get-together above the surface.
A reunion of NCC adventurers past and present is taking place at Clapham Village Hall in the Yorkshire Dales on May 18.
And with the clock ticking down to the big day, the search is on to locate members who have lost touch with the club over the years.
The anniversary party is being organised by Ruth Smith, who comes from Farsley in Leeds.
Her late father, Alan ‘Drus’ Drury was a long-standing member of the club until his death in 1996, aged 49.
Ruth, herself a keen caver, told the Yorkshire Evening Post: “We’re hoping to get in touch with as many people as possible.
“It should be a great event – there are certainly a lot of memories to share!”
Ruth has made contact with about 50 people who have caved with the club in the Dales as well as further afield.
Another 50 or so former members, though, have still to be found.
They include Dave Marsh, who was last heard of living in Thorner and could have rare film footage of the club in action during its early days.
Others who have slipped off the radar include Dave ‘Foxy’ Fox, who has links to the Garforth area, and Michael Collinson, nicknamed Kippax Mick.
Anyone with information about them or who wants further details about the anniversary event is asked to e-mail: email@example.com.
Some people are travelling to the reunion from countries such as America, Canada and New Zealand.
The event will feature a slideshow and an auction where the lots will include work by artists Paul Horner and Carolina Shrewsbury.
The NCC was founded as an offshoot of the White Rose Potholers group in 1963.
Its notable achievements include the extension in the 1970s of King Pot, near Ingleton in the Dales, which at the time was described by one caver as the biggest find of its kind in Yorkshire for a decade.
Members have also been instrumental in putting places such as Mexico and Vietnam on the caving map.