The 12 Most Spectacular Caves in The World

A collapsed cave roof on Kefalonia opens onto an underground lake so clear that the rowing boats appear to hang in mid-air.

When the sun is directly overhead the water turns an electric blue that looks artificially enhanced but isn't.

A short boat trip takes you through the lit chamber and out under the open dome.

A navigable underground river winds more than 8 kilometers through a limestone karst cave system before reaching the sea, its chambers hung with stalactite formations and home to colonies of bats and swiftlets.

Paddled by small boat with a guide, the first kilometer open to visitors passes through cavernous chambers where the ceiling occasionally opens into shafts of light.

Its scale earned it a spot among the New7Wonders of Nature.

A domed sandstone chamber on the Algarve coast with its own crescent of beach and a circular hole in the roof that drops a column of sunlight onto the sand.

It can only be reached from the water, by kayak, paddleboard or tour boat, since swimming across from the neighbouring beach is now restricted.

A limestone hill north of Kuala Lumpur where 272 rainbow-painted steps climb past a 43-metre gold statue of Murugan into a cathedral-sized cavern holding Hindu shrines.

Macaques patrol the staircase and will help themselves to anything loose.

During Thaipusam in January or February the site draws well over a million pilgrims.

A labyrinth of marble caverns carved by wave action into a peninsula on Lake General Carrera, forming swirled chambers and arches in white, grey, and cobalt blue.

Accessible only by small boat, with the water's color and the marble's pattern shifting dramatically with the season and light.

A limestone system under the New Mexico desert whose Big Room is among the largest cave chambers on earth, roofed by a ceiling of stalactites.

You can descend 230 metres on foot through the Natural Entrance or drop straight down by lift.

On summer evenings, hundreds of thousands of Brazilian free-tailed bats spiral out of the mouth at dusk.

A limestone sinkhole near Tulum with startlingly clear freshwater, shallow turquoise pools giving way to dramatic cave passages hung with stalactites.

Turtles and small fish glide beneath snorkelers in water so clear it barely seems real, especially deeper into the cavern sections.

A limestone cave system with an underground river, reachable only by boat across Lake Te Anau.

Deep inside, a grotto ceiling is studded with thousands of glowworms, their bioluminescent threads creating a silent, star-like constellation in total darkness.

Twenty-four kilometres of galleries under the Slovenian karst, entered aboard an electric train that runs two kilometres into the rock before you continue on foot.

The formations range from delicate straws to a five-metre white column called the Brilliant.

An aquarium inside holds olms, the pale blind salamanders locals call baby dragons.

A 240-metre limestone cave in the hills of Guilin, lit throughout in saturated reds, greens and blues that turn the stalactites into something closer to stage design than geology.

A still pool near the end doubles every formation above it.

Ink inscriptions on the walls date back to the Tang dynasty.

A lava tube on Lanzarote formed when the Corona volcano erupted around 3,000 years ago, running six kilometres down towards the sea.

A kilometre of it is open, lit in ochre and green by the artist Jesus Soto, and the tour ends with an optical illusion so convincing that most visitors refuse to believe it until it is explained.

A working salt mine for centuries, Turda has been converted into one of the world's strangest amusement parks — a vast underground chamber 120 meters below ground with a Ferris wheel, mini-golf course, bowling alley and an underground lake with rowboats, all carved from salt.

The cool, still air and echoing acoustics make it feel like an opera house hollowed from rock, unlike any other mine attraction in Europe.