THE wild and rugged landscapes of Scotland may inspire poetry and grace calendar pages, but a raft of hidden gems can equally fire the imagination.

From caves and tunnels to bunkers, mines and crypts, here's our pick of the 10 best underground places to explore.

The Lochnell Mine Experience, Wanlockhead

Mining was once the lifeblood of Scottish industry and the beating heart of many close-knit communities. Typically, it was dangerous work. The hazardous conditions and physical peril involved is largely unfathomable to many of us working sedentary office jobs.

A guided tour of Lochnell Mine – part of the Museum of Lead Mining – gives some sense of what life was like for those tasked with extracting the silvery-grey metal from the hills around Wanlockhead.

The museum has the only underground mine tour in Scotland, allowing visitors to venture into the confines of a 300-year-old timbered passage and drift. Tours last around 45 minutes, with helmets and lamps provided.

Visit leadminingmuseum.co.uk

Glasgow Central Station

If you love social history, then exploring the passageways, vaults and echoing spaces beneath the tracks of Scotland's busiest railway station is a must. Tours are led by gregarious guides with an encyclopaedic knowledge of all things Glasgow Central.

The content centres largely on human stories, such as poignant tales about a makeshift mortuary during the First World War. Grieving relatives faced the bleak prospect of traversing rows of corpses to identify the remains of loved ones who had perished on French battlefields.

HeraldScotland: A tour beneath Glasgow Central station. Picture: Colin MearnsA tour beneath Glasgow Central station. Picture: Colin Mearns

A curious array of objects, such as a 100-year-old wheelchair and a newspaper dating from the 1940s, have been discovered within the station's sealed-up cupboards and walls. Among the highlights is a chance to descend below ground to view a disused, soot-stained Victorian platform.

Visit glasgowcentraltours.co.uk

The Bone Caves and Smoo Cave, Sutherland

If caves are your thing, Sutherland is a great choice. Carved deep into the limestone cliffs, Smoo Cave, near Durness, has three impressive sections: a large sea cave entrance, a waterfall chamber and a freshwater passage.

The Bone Caves, meanwhile, can be found south of Inchnadamph on the A837 and are accessed on foot along a mile-long path. The area gained fame when Victorian geologists John Horne and Ben Peach stumbled across a collection of animal bones in the late 19th century.

Further excavations uncovered remains belonging to wolves, lynx, Arctic foxes and even a polar bear, believed to date from the last glacial period. Human bones and artefacts have also been discovered in the caves.

Visit smoocavetours.com and nature.scot

Scotland's Secret Bunker, Fife

The prominent road signs pointing to "Scotland's Secret Bunker" regularly raise a chuckle and if you've never visited, this Cold War era command centre is packed with fascinating things to see.

Buried 100ft underground, with the entrance hidden in a non-descript farmhouse, the clandestine bunker – now declassified – was built at RAF Troywood, near Anstruther, Fife, in 1953.

HeraldScotland: Scotland's Secret Bunker, FifeScotland's Secret Bunker, Fife

This labyrinth of tunnels, encased in 15ft of concrete, is where government and military leaders would have gathered upon the outbreak of nuclear war and looming attack from the former USSR. Among the facilities are an operations room, dormitories, two cinemas and a cafe.

Visit secretbunker.co.uk

Cawdor Castle, Nairn

In the 14th century – or so the story goes – William, 3rd Thane of Cawdor, set out to build a replacement castle on a less marshy site. To find a location, he followed instructions said to have come to him in a dream and loaded panniers of gold onto the back of a donkey.

William followed the animal as it roamed across his lands. When night fell, the donkey rested under a tree in the steep sided Allt Dearg glen. It was here that construction of the medieval castle tower began, with the tree symbolically incorporated.

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Modern scientific analysis has revealed that the tree died circa 1372, most likely as a result of being deprived of light because the castle had been built around it. It was long believed to be a hawthorn, but in more recent times confirmed to be holly. The tree still stands in the cellar to this day.

Visit cawdorcastle.com

Innocent Railway Path and Colinton Tunnel, Edinburgh

Subterranean adventures abound in and around the Scottish capital with The Real Mary King's Close, South Bridge Vaults and the Edinburgh Dungeon all popular haunts on the tourist trail.

A network of walking and cycle paths around the city includes the colourful, mural-emblazoned Colinton Tunnel on the Water of Leith Walkway. Part of the former Balerno branch line and now revamped thanks to a community art project, it stretches 140m (459ft).

HeraldScotland: Colinton Tunnel, Edinburgh. Picture: Jane Barlow/PA WireColinton Tunnel, Edinburgh. Picture: Jane Barlow/PA Wire

The Innocent Railway Path, meanwhile, was built along a route that ran from Edinburgh to Dalkeith. Widely credited as the oldest train tunnel in Scotland, it covers 518m (1,700ft) and can be used to travel – by foot or bike – south-east from St Leonards towards Duddingston.

Visit edinburgh.gov.uk and colintontunnel.org.uk

Cruachan Power Station, Argyll

Often hailed as one of the finest examples of post-war Scottish architecture, the Cruachan Power Station is an impressive feat of engineering.

Its construction, which began in 1959, is nothing short of remarkable and largely down to the brave efforts of the Tunnel Tigers, a 4,000-strong army of workers drafted into Argyll to drill deep into the granite rockface of Ben Cruachan, creating the "Hollow Mountain".

Today, there is a visitor centre and tour which journeys into the hidden world and workings of the ground-breaking hydroelectric power station. In recent days, renewable energy firm Drax announced plans to expand the complex by 2030, excavating a further two million tonnes of rock.

Visit visitcruachan.co.uk

HeraldScotland: Cruachan Power Station, Argyll. Picture: Jeff J Mitchell/Getty ImagesCruachan Power Station, Argyll. Picture: Jeff J Mitchell/Getty Images

Crichton Crypt Tours, Dumfries

The Crichton, an 85-acre estate on the outskirts of Dumfries, began life as a Victorian psychiatric hospital. In more recent decades, it has been redeveloped into a hub for education and leisure, playing host to concerts, exhibitions and festivals.

The site's rich history, dating back to 1838, is explored by Mostly Ghostly Tours as part of its ongoing series of guided walks around the cathedral-style Crichton Memorial Church, including the crypt and undercroft.

The next tour – for those brave enough – takes place on June 5, sharing a tapestry of spooky tales woven into the fabric of the building and surrounding grounds.

Visit crichton.co.uk

Fingal's Cave, Staffa

Arguably one of the most photogenic caves in Scotland, this bucket list spot gets its eye-catching look courtesy of a quirk of cooling lava that created magnificent basalt columns on the uninhabited Hebridean island of Staffa, similar to those that form the Giant's Causeway in Northern Ireland.

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Fingal's Cave gained its name from the eponymous hero of a poem by the 18th-century Scots poet-historian James Macpherson (also the "translator" of the Ossian literary hoax). The 227ft (69m) cavernous interior is said to boast tremendous acoustics.

Composer Felix Mendelssohn wrote an overture in its honour, artist J M W Turner painted it and author Jules Verne mentions it in three novels, including the famed Journey to the Centre of the Earth. There are regular boat trips for those who fancy a closer look.

Visit staffatours.com

HeraldScotland: Fingal's Cave, Staffa. Picture: Getty ImagesFingal's Cave, Staffa. Picture: Getty Images

Falkirk Tunnel

Let's sum up the mighty Falkirk Tunnel by numbers: it is 630m (2,067ft) long, 5.5m (18ft) wide and 5.8m (19ft) high.

Created 200 years ago and originally used for transporting coal, today it carries the Union Canal beneath Prospect Hill in Falkirk. The towpath is a popular walking and cycling route, continuing all the way to Edinburgh.

It may be illuminated with colourful lights, but there is a darker side to its history. Notorious serial killers Burke and Hare both worked on the tunnel's construction between 1818 and 1822. The canal was also used by unscrupulous doctors to smuggle the corpses of patients to Edinburgh University.

Visit visitfalkirk.com and scottishcanals.co.uk