When London architect Adrian John Waters and Australian chartered accountant Susan Diane Bethell chose Llechwedd Slate Caverns for their wedding in May 1999, they, and district Superintendent Registrar Olwen Jones found themselves a place in the Millenium edition of Guinness World Records.

It was the world’s deepest wedding, 450 feet beneath the surface – a record now shared with many couples.

Different underground venues at Llechwedd Slate Caverns have been licensed for weddings but by far the most popular is  the shoreline of the dramatic underground lake, which tourists normally see at the end of their tour through ten “son et lumiere” sequences, each in a different chamber.

Like the tourists, wedding couples and their guests first have to descend into the Deep Mine on Britain’s steepest passenger railway, which has a gradient of 1 in 1.8 Historically the 16 floors at Llechwedd mines are all identified in relation to the point where the slate was found in 1849, after three years of costly exploration. This became known as Floor 1, the entrance to which is now hidden behind the concrete lining inside the passenger incline, but is 49ft. (15m) beneath the modern working surface. The floors were numbered upwards (1-7), and lettered downwards (A-I), so that passengers board the vehicle on Floor 2, which is at 849ft (259m) above sea level. Alighting at Floor A, 99ft (30m) lower down, passengers eventually descend a further 32ft. (9.75m), via 61 steps to Floor B, by which time they are 450ft. (137m) beneath the summit of the mountain.

Among the impressive display of commemorative plaques at the entrance to Llechwedd Slate Caverns is one celebrating its inclusion in the Wales Screen Commission’s North Wales Film and Television Trail.

Llechwedd has been the venue for three major films and several smaller productions. “The Keep” (1983), part of which was filmed underground at Llechwedd, was a fantasy set in a German-occupied Carpathian castle, beneath which hid an evil force. The famous underground lake was used for some of the most dramatic scenes in “Prince Valiant” (1997), set in the time of King Arthur, and featuring Stephen Moyer,Edward Fox and Joanna Lumley. (An earlier version of “Prince Valiant was also made in North Wales, in 1954, featuring Robert Wagner, James Mason and Janet Leigh). The first Welsh-language full-length cinema film, “Y Chwarelwr”, was made at Llechwedd in 1935, when Sir Ifan ab Owen Edwards was the cameraman. Oddly, perhaps, part of the 1985 Walt Disney cartoon production “The Black Cauldron” was filmed underground at Llechwedd, for computerised adaptation. The characters and locations were a rich blend of Welsh mythology and legend. Taking ten years to complete “The Black Cauldron” was said by Disney Studios to be their most ambitious animated production.   

 J.W.Greaves and Sons Ltd. commenced extracting slate from the Llechwedd Mines early in 1836, taking the raw material from the rich Ordovician deposit laid down around 500 million years ago. Since that time company have built up the reputation of providing high quality blue-grey slate, which has found market places in many corners of the world. 170 years on, the company remains fiercely independent, producing slate for use throughout the country and within the European market place.

Visitors to Llechwedd can go on two underground tours. The Deep Mine and The Miners Tramway. In the Victorian Village re-minted Victorian coins are available from the Old Bank for such delights as a penn’orth of boiled sweets at the Corner shop, or a pint at the Village Pub. Catering includes a café, a coffee shop and the Miners Arms.

Couples planning to marry underground at Llechwedd need to book the date and time with both Llechwedd Slate Caverns (Tel: 01766 830306) and with the Superintendent Registrar for the Ardudwy District, in the County of Gwynedd, whose office is in Church Street, Blaenau Ffestiniog (Tel: 01766 830217).