Most Dangerous Caves You Must Never Enter

Let's explore the Cave of the Crystals, the Nutty Putty cave and some of the most beautiful, yet dangerous caves in the world!

July 21, 2023・

19 min read

Caving, or spelunking, is not an activity for the faint-hearted. A term used for exploring the extremes of cave systems, the deeper you go, the less light, space, and even breathable air there is. It's the worst nightmare of any claustrophobe!

But imagine squeezing yourself over jagged rocks and through impossibly tight spaces in the pitch black, when all of a sudden you come across a cave lined with crystals stretching from the cave’s floor to its ceiling! But, as mesmerizing as this place looks, you wouldn’t have long to marvel at its impossible beauty.

Let's uncover what makes this giant crystal cave one of the most deadly natural phenomena in the world, and look at some other caverns that, despite their splendor, you should never step foot in!

Cave Of The Crystals

Whether it’s their supposed healing powers or the way they sparkle in the light, we humans have been obsessed with crystals for as long as we can remember. Back in 1910, when miners from Naica, Mexico, discovered a cavern with short, sparkly minerals lining the walls, you can imagine their excitement!

They’d found the Cave of Swords, a crystal-filled cavern, some 390 feet below ground. The miners didn’t know this at the time, but Naica lies above an underground magma chamber some 2 or 3 miles below the Cave of Swords.

Over the course of some 500,000 years, the magma-heated groundwater and oxygenated surface water gradually began to change the minerals in the area. Then, as the temperature of the cave started to drop below 133 °F, gypsum crystals slowly began to form.

In the Cave of Swords, this temperature transition happened relatively rapidly, and today it sits at around 116°F, meaning the crystals only had a chance to grow a little over 3 ft in length. Still, a 3 ft crystal is a pretty magnificent thing to behold, let alone a whole cavern full of them!

The Cave of Swords was the prize find of Naica for 90 years, until the year 2000 when miners were drilling a new tunnel through the Naica Fault. They delved 600 feet deeper than the Cave of Swords, and suddenly stumbled across an even more jaw-dropping chamber: The Cave of the Crystals!

It was completely flooded and had to be drained to get a better look, revealing that the walls and floors were chock full of gigantic gypsum beams. Not even a year before, The Pulpí Geode had been discovered in Spain, boasting similar gypsum crystals that reached some 6 ft 7 inches in length.

But these were a whopping 37 ft in length, more than 5 times the size of those in Pulpí, with the biggest of them weighing a backbreaking 55 tons, making them the largest natural crystals to ever be discovered! But the mass of these structures isn’t the only thing stopping you from nabbing a souvenir or two.

The Cave of the Crystals is a sizzling 136°F, which is the reason why these crystals have been able to grow so big in comparison to those in the cooler Cave of Swords. For some context, though, that’s hotter than the maximum temperature ever recorded on the planet’s surface.

Not even if you pack some water and a portable fan you'd be good to go. This cave is a giant sweatbox, with humidity levels reaching 99%. Because the air is so hot and humid, the coolest place in the cave would be the inside of your lungs. As a result, water would condensate there, effectively drowning you from the inside out!

Without proper protection, people can only endure ten minutes of exposure in the cave at a time! However, once mining operations in the area ceased in 2015, the cave was allowed to re-flood, protecting the giant crystals within and closing it off to all researchers and visitors alike.

So, unless you like the idea of scuba diving in a cave 980 ft underground with almost no natural light, these incredible crystals and the death trap they’re found in are off-limits for the foreseeable future!

Mount Rainier Paradise Ice Caves

Ice caves like Mount Rainier’s Ice Caves in Washington form when temperatures rise and meltwater runs through or under a glacier, leaving behind mottled passageways or caverns within the glacier itself!

But, despite the pretty shapes, this isn’t a place that you want to dawdle in, ice caves are really cold. Typically these frozen caverns are a bitter 15°F. Your normal body temperature is around 98.6°F, but if it drops below just 95°F, your body enters hypothermia. This is when your heart, nervous system and other organs stop functioning normally.

If left untreated and exposed, you could be dead in a matter of minutes. So, staying there too long, or failing to wrap up properly could be fatal! Yet, it turns out that chilly conditions here are actually the least of your worries. During the warmer months, melting occurs in the Mount Rainier ice caves. Chunks of ice, the size of small cars have fallen from the cave’s ceiling!

Even if you manage to dodge a bulky block of ice, you may still not get out of there in one piece. Ice caves, like the ones at Mount Rainier, are prone to collapsing due to melting in the warmer summer months. As recently as 2015, collapses in nearby ice caves have claimed several lives and left many badly injured.

Lechuguilla Cave

In New Mexico, you’ll find the entrance to the 8th longest-explored cave in the world, Lechuguilla Cave. At 150 miles long, reaching 1604 deep, it’s the second deepest explored cave in the entire US! And it’s also considered to be the most beautiful and well-decorated cavern in the world, with thousands of rare geological formations hidden within!

From giant gypsum chandeliers, and 15 feet tall soda straw stalactites, to some peculiar bubble formations stained in a perfectly straight line by the slowly decreasing water level over hundreds of thousands of years! But be warned, you don’t want to spend too long soaking up these stunning sights, because the humidity levels here can hit 100%!

In such humid conditions, when the air’s saturated with water, our sweat can’t evaporate, preventing us from cooling down. While trekking through this super-long cavern may sound like a good way to shed a few pounds, walking in such testing conditions could put you at risk of exhaustion and dehydration.

To make matters worse, Lechuguilla also contains many ditches and drops, with some vertical pits plummeting down a vertigo-inducing 300 feet. For reference, falling down there would be like jumping off the Statue of Liberty! Exhaustion, pitch black, and dramatic drops probably aren’t the best mix.

It’s so dangerous that the historic cave has been closed to the public, with only the most experienced explorers and researchers permitted access. And even then, back in 2014, a rescue team was called to retrieve a stricken caver volunteer who’d only descended 180 ft in the cave, barely 10% of its known depth.

Grjótagjá Cave

Tucked away off Iceland’s Lake Mývatn, lies Grjótagjá cave. It may not look like much from the outside but, inside, this cavern is home to crystal-clear, bright, beautiful waters. The location is so picturesque that it was even the hook-up place for Jon Snow and Ygritte in Game of Thrones! Yet, that ain’t the spiciest thing about this cave.

The standout feature of Grjótagjá is its warm waters, which are heated by volcanic activity deep within the earth. Up until the 1970s, the cozy temperature of Grjótagjá’s water made it a popular bathing site, with people flocking to the cave for some respite from the ice-cold outdoors. But the good times didn’t last long.

During the 70s and 80s, volcanic activity increased, raising the water to a scalding 140°F. At this temperature, just 5 seconds of exposure to this water could cause life-threatening 3rd-degree burns!

Fortunately, the temperature of the water has since cooled down to a more comfortable 110°F. Still, with the constant threat of volcanic activity unexpectedly heating the water again, taking a dip here is one heck of a high-stakes gamble! So, if you’re not looking to get boiled like a potato, you should think twice before stepping foot in Grjótagjá’s waters!

Abaco Island Crystal Caves

The Bahamas is best known for its pristine, white sand beaches and heavenly waters. But it’s actually underground and underwater that the scenery gets even more picturesque. Beneath the warm pine forests of Abaco Island in the northern Bahamas, lie a series of marine caves extending for over 9 miles.

And it’s in these caverns, divers can find the Glass Factory; caverns full of intricate calcite formations! These stunning crystal roses, along with stalactites and stalagmites, litter the ceilings and floors, which make the entire place look both impossibly beautiful and dangerous.

These formations all developed during the ice ages, when the sea level dropped dramatically, leaving the caves dry and dripping with mineral-rich waters. Gradually, these mineral deposits built up into the structures lining the ceilings and floors of the Glass Factory today.

Now flooded, it may look like these fascinating formations are capable of dealing any clumsy divers a sharp stab, but it turns out that these are incredibly delicate. That’s not to say that there aren’t other dangers lying in this watery wonder, however.

Suspended clouds of hydrogen sulfide can be found throughout the caves at Abaco Island. Not only does hydrogen sulfide emit a smell like rotten eggs, but it’s also pretty damn dangerous. While divers breathe compressed air through dive tanks, hydrogen sulfide can penetrate through wetsuits and skin, leading to nausea, delirium, and even death!

Cueva de Villa Luz

As you make your way down into Mexico’s Cueva de Villa Luz, the first thing you notice are the pools of beautiful turquoise water. That’s until you learn the terrifying truth about this place. A cloudy tinge in the water isn’t the work of an overpriced bath bomb, it’s our old foe again, hydrogen sulfide.

But unlike the pockets of it found in the Abaco Islands, this gas isn’t just in the cave’s water, it permeates the air too! Swimming through hydrogen sulfide can get ugly but its presence in the atmosphere is just as dangerous. All it takes is 5 hydrogen sulfide particles per million, or PPM, to lead to nausea and breathing problems.

Yet, the concentration of hydrogen sulfide in Cueva de Villa Luz can reach a dizzying 210 ppm! At these levels, explorers can expect severe conjunctivitis, irritation to their respiratory tract, as well as pulmonary edemas, which are potentially fatal buildups of fluid in the lungs.

And just in case that wasn’t deadly enough, indigenous Zoque people conduct an annual religious ceremony here, which turns Cueva de Villa Luz into an even bigger deathtrap. Each year, they throw the ground-up paste of the barbasco root, known as rotenone, into the water.

Rotenone, which is a toxic compound, kills the fish that live in the cave’s water. But it’s not just Nemo who needs to watch out for this perilous paste, as humans too can feel the effects of this stuff. Ingestion of rotenone can cause inflammation of the throat, gastric pain, vomiting, incontinence, and even seizures.

Orda Cave

Underneath Russia’s Ural Mountains lies Orda Cave, a place that looks more like a swimming pool in a luxury spa resort than a cavern! The waters of Orda Cave are kept crystal-clear thanks to the gypsum material that the cavern’s made out of.

Essentially, gypsum attracts clay particles together to form clumps, known as floccules. When these floccules get large enough they eventually increase in weight and sink to the bottom of the water. As a result, divers in the cave are able to see over 150 feet in front of them.

Sounds like these are idyllic conditions to take a quick swim in. However, at Orda Cave, the water temperature drops down to a bone-chilling 40°F. Unsurprisingly, the only way to survive a dip here is by wearing a wetsuit. Without it, just 5 minutes in this wintry water will lead to a loss of dexterity. 25 minutes later, you’re likely to lose consciousness. Any longer, and you’ll face a frozen finish.

The waters of Orda Cave aren’t only home to freezing temperatures, however. Some divers have claimed they’ve seen a maiden in a white gown, known as "The Lady of the Cave" floating in the waters. She’s said to protect and guide divers that enter the perilous cavern.

The Lady of the Cave hasn’t saved everyone, though. The freezing waters of Orda have apparently claimed the lives of around 300 divers throughout the years. Who’d have thought trusting a mysterious, floating underwater figure with your life could lead to a bad ending?

The Shaft And The 1973 Diving Accident

In 1938, a farmer in South Australia stumbled across a one-foot-wide hole in his field. But this wasn’t the burrowed home of a rabbit or badger. It turned out to be the opening to The Shaft, a giant underground cave stretching down far, far below.

While the way into this place is small, the main chamber was enormous. In all, the colossal cavern stretched down some 460 feet and it’s underwater, so to explore it anyone brave enough needs a wetsuit!

Sinkholes like this exist all over Australia, with some, like the nearby Kilsby sinkhole, big enough to explore scuba style! But, as mesmerizing as shots of these sinkholes look, The Shaft is the site of a truly terrifying tale.

Back in May 1973, eight divers set about exploring the submerged cavern. Everything was going to plan until the divers left the sunlit chamber and stumbled upon a side tunnel. At this point, they were at depths where the effects of nitrogen narcosis could be felt, somewhere between 100 ft and 300 ft.

Nitrogen is a major part of the air we normally breathe. But when divers descend into deeper water, the pressure of the nitrogen leads to more of its particles getting absorbed into the bloodstream. And, the higher the nitrogen concentration in the bloodstream, the slower the nervous system becomes.

As a result, sufferers of nitrogen narcosis experience intoxicating effects, like confusion and disorientation. Luckily, some of the more experienced divers recognized their nitrogen narcosis symptoms and returned to the surface. However, four still remained deep underwater.

To make matters worse, they disturbed the silt sediment in the side tunnel, obscuring their vision completely. Imagine that, not only are you delirious some 100 feet underwater, but you also can’t see anything around you.

Practically blind, and with the ever-increasing effects of nitrogen narcosis, the four remaining divers sadly never made it back out of The Shaft. Kilsby sinkhole is no better, having claimed some 12 lives in similar accidents from 1969 onwards. So, no matter how enticing those sinkhole waters may look, stay out of those holes!

Nutty Putty Cave

It’s easy to get lost in the rolling hills of the west of Utah Lake in Utah. However, peaceful as the place looks, it’s actually the site of one of the world’s deadliest caves. This hellhole, called Nutty Putty, contains some 1,400 ft of chutes and crazily claustrophobic tunnels.

For some reason, hardened cavers relish crawling through those teeny-tiny spaces. One such explorer, by the name of John Jones, did exactly that in November 2009. About an hour into the expedition, John attempted to crawl head-first through a tight passage in the cave, squirming forward with his hips, stomach, and fingers.

But suddenly John realized that he’d gone too far. He was upside down, and stuck, with no room to turn around. And all of this was happening almost 400 feet from the cave’s entrance. Completely trapped, John tried to keep moving forward. He exhaled, allowing his flattened chest to fit slightly further down the tunnel.

But, when John inhaled again, his chest expanded and now he was even more firmly wedged. Luckily, John’s brother, who was with him, came across his trapped sibling and called rescue teams for help.

Workers tried to pull Jones out leg-first, using a rope-and-pulley system. Slowly, the rescue workers began to draw John out of the tight passage, but then disaster struck. An equipment failure plunged John back into where he’d been trapped, and now he was even more stuck.

Despite continuous efforts by the rescue workers, John soon became unresponsive. After more than 24 hours upside down, and wedged between the smallest of gaps, the pressure on John’s body became too much. Sadly, John didn’t make it.

And even after his passing, the mission to retrieve John’s body was deemed too dangerous. So, a decision was made to make the cave a resting place for John. Nowadays, Nutty Putty is completely closed off, and the memorial dedicated to John Jones serves as a reminder of just how lethal this cave is!

Little Neath River Cave

Most of the time, there’s something super peaceful about a gently flowing river. But the one in the image below isn’t just a river, it’s also the entrance to the deceptively dangerous Little Neath River Cave.

The cavern, found in South Wales, has become a popular exploration spot with experienced cavers. To get through the entrance alone, cavers have to crawl on their hands and knees on the riverbed, before entering the cavern through a gap that’s barely wide enough for a person to fit through.

And it’s not just the entrance that’s a tight squeeze. Some of the passageways in this cave are so confined that cavers have to remove their helmets in order to fit through! But getting stuck in Little Neath River Cave isn’t the only thing that explorers have to watch out for. It’s also prone to flooding if there’s a sudden surge of rain.

Can you imagine the turmoil of struggling to squeeze through the tight gaps of this cavern, and then all of a sudden you’re up to your neck in water? If that wasn’t terrifying enough, cavers have to navigate a 500-foot-long passage with a ceiling so low, they must crawl along on their hands and knees while they’re almost completely submerged in water!

Those brave enough to take on Little Neath River Cave are at least rewarded by the incredible calcite formations that this cave has to offer. Cool as that looks, there’s no way you’ll see me crawling along a riverbed to catch a glimpse of it!

Deep Caverns

Located in Abkhazia, Georgia, Krubera Cave is deep. So deep, that it’s known as the "Everest of caves", with the deepest explored point laying around 7,215 feet below. That’s around a quarter of the height of Everest, but it’s still about the same as 5 Empire State Buildings stacked on top of one another.

In all, a descent down this colossal cave system and back up can take an eye-watering 2 weeks! It is a terrifying, winding, wet series of passages that seems to never end, with some sections so flooded that diving equipment has to be used to move on. Luckily Krubera isn’t just a straight drop-down, but that doesn’t mean you couldn’t do some damage with a fall.

One particular pit, known as the Big Cascade plunges down almost 500 feet. Imagine stumbling across that in the dark! Terrifying as that sounds, some caves possess even deadlier vertical drops, usually caused by erosion from powerful underground waterfalls over thousands of years.

Inside Georgia’s Ellison Cave is Fantastic Pit, a shaft dropping straight down a stomach-churning 586 feet! If you took a misstep and fell down this hellhole, it’d effectively be like jumping off Canada’s Space Needle.

If the Fantastic Pit doesn’t give you vertigo, this next place certainly will. The Miao Keng shaft in Tian Xing, China descends down a skin-crawling 1,660 feet, making it the deepest unbroken vertical shaft in the entire world. If you were to stumble down this sizeable shaft, you’d be falling for over 10 seconds!

Kitum Cave

With lush, green vegetation surrounding it, and a waterfall streaming over its entrance, Kitum Cave in Mount Elgon National Park, Kenya, wouldn’t look out of place in a holiday brochure. But picturesque as this scene looks, Kitum Cave holds some sinister secrets that make it one of the world’s deadliest caves.

For centuries, elephants have ventured into the cave to scrape away at the cavern’s salt-rich walls. While meeting an elephant in a cave would be a once-in-a-lifetime experience, with these burly beasts flattening around 500 humans a year, you wouldn’t be too keen on stumbling across one in a dark cavern.

But for some, the risk of an elephant encounter wasn’t enough to put them off visiting this place. In 1980, Charles Monet went exploring deep into Kitum Cave. While he wasn’t struck down by an angry animal, this cavern had an even nastier surprise in store for him. After he’d finished exploring, Monet left Kitum Cave and returned home.

Soon after his excursion, Monet came down with an excruciating headache. Fever, nausea, and vomiting quickly set in, forcing him to visit Nairobi Hospital. Not long after his vomit was black, and fluids leaked from every orifice in his body. Sadly, it all became too much, and Monet crossed the great divide.

7 years later, a young Danish boy was admitted to Nairobi hospital, with the exact symptoms that Monet had experienced. So, what did the two of them have in common? They’d both visited Kitum Cave.

A research investigation was launched to find what in the cave was the source of the men’s demise. Turns out, it was bat poop. The excrement of Egyptian fruit bats, deep inside the cave was found to contain Marburg Virus, a virulent disease that causes the gruesome symptoms seen in the two men. In fact, it’s so deadly that the average case fatality rate is 50%.

I hope you were amazed at these dangerous caves that you must never enter! Thanks for reading.