City Hall Station, USA
This New York City subway station opened to great fanfare in 1904 but is today eerily silent. The architectural grandeur of the disused station – stained glass windows, skylights and brass chandeliers adorn its curved walls and arched ceilings – can only be viewed by passengers as train #6 loops back uptown or at occasional events like this Centennial celebration.
Yucatan’s cenotes, Mexico
The limestone shelf that forms the Yucatan Peninsula is riddled with sinkholes called cenotes. The most stunning are enormous deep wells of turquoise water set in dramatic caverns and considered by the Maya to be gateways to the underworld.
Puerto Princesa Underground River, Phillippines
A guided boat tour beneath low-lying limestone cliffs and through vast unlit sepulchral chambers is an unforgettable and magical experience. This unique underwater river system is said to be the longest in the world and is visited by more than five hundred thousand tourists each year.
Reed Flute Cave, China
Named for the reeds once found outside the entrance, this natural limestone cave is a brightly lit magical fairyland with impressive stalactites, stalagmites and rock formations. This reflective pool in the heart of the cave makes for a breathtaking spectacle.
Mary King’s Close, Scotland
Spooky tours led by costumed actors explore the warren of underground streets and spaces beneath Edinburgh’s Royal Mile. Tenements had been built on the steep hillside and when work on the City Chambers began in 1753, the tops of existing houses were simply sliced through and the new building constructed on top.
Ajanta Caves, India
Hewn from the near-vertical sides of a horseshoe-shaped ravine, the caves at Ajanta occupy a site worthy of the spectacular ancient art they contain. The remarkably preserved murals, carvings and sculpture dating from 200 BC to 650 AD are considered masterpieces of Buddhist religious art.
Derinkuyu Underground City, Turkey
Located in a rain-washed basin in Southern Cappadocia, this extensive ancient underground city contains family rooms, communal areas, stables, churches, wine and oil presses, chimneys to bring fresh air, wells to bring fresh water, a school complete with study rooms, and even makeshift tombs. Thousands of people could retreat behind stone doors to safety.
Catacombs of Paris, France
Tourists can wander through miles of claustrophobic, dark and damp caves, tunnels and quarries said to hold the bones of around six million Parisians. Lining the gloomy passageways, long thigh bones are stacked end-on, forming a wall to keep in the smaller bones and shards, which can be seen in dusty, higgledy-piggledy heaps behind.
Cheddar Caves, England
Beneath the towering Cheddar Gorge in the southwest of England, the Cheddar Caves were scooped out by underground rivers in the wake of the Ice Age. Today the vast caverns are floodlit so that visitors can gaze upon beautiful stalagmites, stalactites and rock formations mirrored in glassy pools.
Kverkfjöll Glacier Caves, Iceland
Lurking beneath Iceland’s stark interior is a frighteningly active volcano whose intense heat melts ice from the base of the glacier. The tunnels and caverns etched by the rivers are enthralling frozen palaces that stretch for over 2km and are best explored with an experienced guide.
Capuchin Ossuary, Italy
This macabre attraction beneath the Church of Santa Maria della Concezione in Rome displays the bones of more than 4,000 friars who died between 1500 and 1870 in elaborate and ornamental designs along the walls.
Casemates du Bock, Luxembourg
Beneath the northeastern corner of Luxembourg City's old historic district, the vast network of underground passages and chambers here are a clear legacy of the country’s strategic position within Europe. Now a World Heritage Site, what remains of the underground ramparts is eerie, claustrophobic and utterly fascinating.
Grotto di Nettuno, Sardinia
Reached either by boat or by 656 vertiginous steps carved into the face of the cliff, these stunning natural caves became a popular tourist attraction after being discovered by fishermen in the eighteenth century. Stalactite and stalagmite formations and a saltwater lake are highlights inside.
Wieliczka Salt Mine, Poland
Placed on the original UNESCO World Heritage list in 1978, this astounding underground mine not far from Kraków is visited by more than one million tourists each year. Nine levels have more than 300km of galleries with works of art, altars, and historic and religious figures sculpted in the salt.
Grotte de Pech Merle, France
Original prehistoric cave paintings can be viewed close to the village of Cabrerets in southwest France. The astonishing rock art depicting bison and mammoths was discovered in 1922 and short of inventing a time machine, this is the closest you’ll get to the mind of Stone Age man.