Cornwall’s Underground Attractions to visit

Date Posted: 20 Dec 2023

Kirstie Newton goes on an underground adventure in Cornwall to seek out the best attractions that remain concealed, discovering Cornish history from times gone by.

Underground, overground… as the song used to go. While Cornwall is famed for its coastal scenery and beautiful countryside, there are several opportunities to find out what lies beneath. Whether you’re a thrill-seeker, a historian or a family in search of a good day out, don’t limit your options to daylight – try one of these.  

PK Porthcurno

Eastern House, Porthcurno, Penzance TR19 6JX 

01736 810966

Cornwall played a crucial role in Allied communications during the Second World War, and nowhere is that more evident than in the Grade II listed underground telegraphy station at PK Porthcurno. This top-secret bunker hid the Porthcurno Telegraph Station, and was protected by armed guards and bombproof doors. Special features included an automated relay system and wireless room, and a secret escape tunnel – 120 steps hewn through solid granite, built in case of invasion by enemy forces. The current exhibition explains the important role telegrams played in the war, and how conflict transformed the valley and the lives of the people who lived and worked here – you can even see an unexploded bomb that fell on a Porthcurno farm. 

Carnglaze Caverns

St Neot, Liskeard, PL14 6HQ 

01579 320251  

On the southern edge of Bodmin Moor, in the steep-sided Loveny Valley, Carnglaze is Cornwall’s only underground slate mine. Originally an open-cast quarry, its fortunes changed over 300 years ago when miners started digging underground by hand, unearthing the dark blue slate that was used throughout south-east Cornwall and beyond. 

A self-guided visit will take you 150m into the hillside and 60m below ground. You will be briefed and equipped with a route plan and safety helmet, then left to roam three large caverns at leisure, reading the story of Carnglaze on information boards. In the first cavern, you can browse a comprehensive collection of South West minerals; take a flight of 50 steps down to the other two caverns, one of which is flooded and forms an underground lake with crystal-clear water. You can even get married here – a truly magical place to tie the knot.
A tour usually takes around half an hour. Numbers are limited so pre-booking is advised. Wear stout footwear and warm clothes – it’s chilly down below. Afterwards, wander among eight acres of ancient oak woodland.
The Rum Store is now a popular events venue, with future performances including Glastonbury favourites Wille and the Bandits (March 30) and folk titans Show of Hands (May 17).

Shipwreck Treasure Museum

Quay Road, Charlestown PL25 3NJ

01726 69897 

Charlestown’s Shipwreck Museum sits atop a network of tunnels created as part of St Austell’s china clay industry during the reign of Edward VII in the early 1900s. Visitors can follow the original cart tracks, and touch the walls where the historic white china clay dust still remains.
Charlestown was a vital port during Victorian Britain and, following the decline of St Austell’s copper mines, the clay and stone business became its main industry from 1906 onwards. In 1907, the Lovering clay dry was erected where the museum now stands, and clay slurry was piped from Carclaze to Charlestown to be transformed into a saleable product. The tunnels were built to transport clay between the clay dry and boats waiting in Charlestown harbour; they remained operational until 1968, by which time they had fallen out of use due to improvements in road and rail infrastructure.
The public now has full access to the subterranean passageways, which are often used for special events, including a very special Christmas experience involving lots of fairy lights! In the museum above ground, you’ll find 8,000 finds from over 100 wrecks. See the only intact barrel of coins ever recovered, feel the weight of a cannon ball and imagine the devastation it wrought in battle at sea.  

Geevor Tin Mine Museum 

Pendeen, Penzance, TR19 7EW 

Geevor is the largest preserved mining site in the country, and little has changed since it closed in 1990 – to the point that The Dry, or the miners’ change room, remains almost exactly as it was the day the miners came up to surface for the last time. It’s now a visitor attraction, and you can walk through tunnels made by men and boys 200 years ago. Dating back to the 18th century, Wheal Mexico was part of the tin and copper mining industry that dominated Cornwall, providing the bronze used in machinery during the Industrial Revolution, from factories producing cotton and woollen cloth in the north of England to buttons in Birmingham and ships on Clydeside. The Mill buildings contain mining equipment that was used to process the rock brought up from underground to produce the precious tin concentrate that Geevor sold, while the museum relics collected over the years by volunteers, enthusiasts and historians: rocks and minerals, mining tools, photography and recorded oral histories, maps and plans, and the Holman Collection of impressive engineering artefacts. Levant Mine and Beam Engine is a scenic 10-minute walk away along the coast path.

Cornwall Underground 

St Just  

Are you an adrenaline seeker? If so, top of your list of things to do in Cornwall should be visiting a Cornish tin mine with this passionate group of mine explorers, historians, and outdoor activity enthusiasts. Founded in 2019, Cornwall Underground offers guided tours of privately owned Cornish tin mines in and around the St Just mining district, part of the Cornish Mining World Heritage Site. Its guides have many years’ combined experience in walking, crawling, abseiling and climbing miles of passages and shafts, re-tracing the footsteps of miners who were there hundreds of years before. The entry level mine tour is three hours and suitable for age 10+. Next up is the Underground Adventurer (14+), a complete through-trip including 200ft of descent, requiring abseiling, traversing and more. Extreme (18+) covers two mining sites in one day.