10 of the best caves in the world

If you have certain expectations from somewhere called ‘Mammoth Cave’, that is entirely understandable. Mammoth Cave in Kentucky is the world’s longest known cave system, an incredible 420 miles of subterranean wonder. That’s twice as long as the next longest, by the way, although it isn’t unusual for the US to go all out on such things. Madly, the cave is home to some vast theatres and avenues, and tours have been known to last more than six hours.

Slovenia has a lot of caves, ranging from the mainstream tourist extravaganza of Postojna to the fragile Križna Jama, but the cavernous theatres of Škocjan give it a leg-up on the competition. A Unesco World Heritage Site since 1986, this gargantuan expanse is arguably the most significant limestone cave in the region, with biological importance allied to careful tourism and local respect. People have been coming to gawp since the beginning of the nineteenth century, and tours are conducted in a wide variety of languages. 

Glowworms, glowworms, as far as the eye can see. Okay, not literally, but the Waitomo Cave system on New Zealand’s North Island is famous for the fluorescent fauna that light up the walls, giving it the not-particularly-creative but completely acceptable ‘Glowworm Caves’ nickname. They are more accessible than most caves on this list, with rafting and adventure tours available to those looking for something a little more adrenaline-heavy.

What an incredible, incredible sight. The dark and dingy nature of underground life conjures something in our imaginations, but the Marble Cathedral in Patagonia shimmers without such requirements. The most beautiful cave on the planet? Beauty is subjective, but it is difficult to look past the case made by the cerulean pillars and vaulted ceilings of this stunner. Found on the shore of the General Carrera Lake in Chile, the Marble Cathedral is a pilgrimage well worth making.

Sailors avoided this place for centuries because they believed it was haunted by witches and monsters, but modern tourism has since proven them very silly indeed. Sunlight filters into the cave through a teeny-tiny entrance (visitors have to lie flat in a boat to get in), filling the space with a stunning blue light that gives the cave its moniker. Swimming is forbidden and rightly so, but visitors to the Blue Grotto usually get more than enough enjoyment from, you know, just looking at it. The cave is found on Capri in the Bay of Naples.

Natural caves don’t come much larger than Sơn Đoòng, close to the border between Laos and Vietnam. This mammoth abyss has the largest cross-section of any known cave on the planet, a vast area that is difficult to describe. Supposedly, a Boeing 747 could fly through without damaging its wings, but that doesn’t really do justice to the vastness of Sơn Đoòng. The stalagmites here are pretty massive too, with some reaching up to a whopping 70 metres.

China’s Reed Flute Cave is also known as the ‘Palace of the Natural Arts’, and that should tell you plenty about what to expect. Named after the reeds that grow outside (which are used to make flutes, obviously), the Reed Flute Cave’s walls are peppered with inscriptions from centuries gone by – proof if proof were needed that people have been paying attention to this place for a long old time. The interior of the cave is also lit up by multicoloured lights, giving it a real otherworldly theme that adds weight to the nickname. 

It is pronounced Thrihnukagigur, if you were wondering. No matter how difficult it is to say, this dormant volcano in Iceland is even more difficult to get one’s head around. This is the only volcano on the planet where you can actually go inside and explore the magma chamber. If that doesn’t whet your appetite, maybe this travelling lark isn’t for you. Half volcano, half cave, all awesome. 

No, your eyes aren’t deceiving, that is indeed a mass of Buddha statues hanging out inside the Pak Ou Caves. The statues have been left over the years by believers hoping for better times, although the caves are now more of a stop-off on a tourist jaunt down the Mekong river than a pilgrimage site. The caves have a curious position overlooking that famous river, meaning boats stop nearby and visitors actually have to climb a staircase to get in. Makes a difference from taking a brave leap into the abyss, that’s for sure.

A stunning sea cave on the uninhabited island of Staffa, Fingal’s Cave is Scotland at its rugged best. Named after the hero of a poem by eighteenth-century poet James Macpherson, this mysterious cavern was discovered in 1772 (well, brought to the attention of the masses) and has become an integral part of folklore ever since, not to mention arts and culture. It isn’t hard to see why, as the thrilling entry to the cave ticks all the boxes when it comes to the supernatural subterranean world. The natural acoustics of the cave are famously fantastic.