11 of the world's weirdest (or scariest) holes
Saturday, September 1, 2018, 3:45 PM - The town of Oxford, N.S., has been grappling with an ever-expanding sinkhole over the past few days, whose growth threatens popular landmarks.
There's a kind of awful fascination people have with sinkholes that can open seemingly at random beneath a home or a vehicle, but any hole that offers us a glimpse into the earth's depths has a certain allure.
We've put together this list of the strangest, or scariest, holes known to humanity. Read on.
The Bayou Corne, Louisiana
Even the mere threat of sinkholes can be a nightmare for property owners: You can take every precaution to keep your home safe, secure and insured when suddenly the landscape outside your window starts eating itself.
Go to around the 15-second mark of this YouTube video:
That's the Bayou Corne sinkhole, and you just watched it silently suck those trees down into the depths of the Louisiana swamp.
It was first discovered in August 2012, prompting Louisiana to declare a state of emergency. Since then it's only grown, reaching nine hectares at last count, and it's forced the evacuation of around 350 nearby residents, many of whom planned to retire there (When the landscape isn't sinking into oblivion, it's actually a nice spot).
It seems to have been due to the partial collapse of a salt dome, an underground salt deposit, and the company that operates it has been fined $260,000 and, along with two other companies, was found to be at fault for the disaster by a state judge (several residents have accepted buyouts).
Making matters worse: Toxic gas was detected near several of the area's homes, and while the amounts aren't high enough to be a threat, the gas is one of the reasons officials say the evacuation could last several years.
The Guatemala City sinkhole
This sinkhole in Guatemala City, meanwhile, isn't in a rural area, it's smack-dab in the middle of one of Central America's largest cities:
It opened up in 2010, and when you look at the aerial pictures, it looks like a bad photoshop. But it's actually 30 metres deep and 20 metres across, so big that in the shot above, you can't even see the bottom.
These guys took a camcorder to the edge of the massive hole, displaying more courage (or foolishness) than we would:
A small factory plunged into the depths, along with a security guard whose body was never recovered.
Very heavy rains of a metre or more from Tropical Storm Agatha are often cited as one of the causes of the collapse, but the tipping point was the poor sewage system beneath the area, which allowed water to seep through the loose volcanic pumice on which much of Guatemala City is built.
With that kind of foundation, the city is no stranger to sinkholes, and the 2010 hole is about the same size as one in 2007 that killed three people.
Soon after the 2007 hole opened up, the government redirected sewer pipes in the area at a cost of $2.7 million, and filled the hole with a special kind of concrete at an unknown but probably hefty cost. Repairing the 2010 hole probably cost at least as much.
The Great Blue Hole, Belize
And off the coast of Guatemala’s neighbour Belize, we have this ominous, but beautiful submarine sinkhole:
Image Source: USGS/Wikimedia Commons
You’ve likely seen it before, and it’s one of countless underwater sinkholes found from Australia to the Red Sea to the Caribbean.
At 300 metres across, and 125 metres deep, it’s believed to have formed thousands of years ago, when sea levels are lower than they are now. A dive team led by the legendary mariner Jacques Cousteau found stalactites, which only form in the presence of dripping water, around 40 m down, although the chemical composition of the site is such that the waters at the hole’s deepest point are poor in oxygen and lifeless (it's the dark spot in this orbital shot).
Image Source: Axelspace Corporation/Wikimedia Commons
It’s popular with divers and recreational mariners, even though we just can’t shake the feeling of dread when we think about looking over the side and seeing a black, forboding abyss instead of the shallow turquoise of the rest of the reef.
Didn’t seem to bother these skydivers, though:
The Great Blue Hole is not the deepest underwater sinkhole, believe it or not.
That crown goes to Dean’s Blue Hole, which is an astounding 200 m in depth. It’s a Mecca for freedivers looking to break the record for greatest depth reached without breathing apparatus (like the guy below).
One person who tried ended up dead. Goes to show how, in the natural world, beauty and danger can coexist quite comfortably.
The Sacred Cenote, Mexico
Back on shore, this sinkhole is a place of death not by an accident of nature, but by design:
Image Source: Altairisfar/Wikimedia Commons
It’s known as the Sacred Cenote, steps away from the ruined Mayan city of Chichen Itza on the Yucatan Peninsula.
It’s just one of many naturally occurring sinkholes eroded into the limestone base that makes up much of the thickly-jungled region, and when it was unearthed more than a century ago, divers recovered not just bowls, cloth, carvings and artifacts, but also several bodies of children and adults bearing signs of human sacrifice.
Sounds awful, but to the ancient Mayans it was essential to appeasing the rain god Chaak. The Yucatan has no real rivers, and these sinkholes were an essential source of water in a region where drought could see the water table drop by 7 m or more.
The Sacred Cenote is pretty murky as you can see, but others can be quite clear and are popular with cave divers.
The Mayan city-states were an advanced and populous civilization that needed a steady supply of water, so making sure the rain god was satisfied was something they took very, very seriously.
How seriously? Well, one of the Mayans’ many innovations was a special kind of dye known as Maya Blue, a resilient pigment that retained its sparkle even after centuries of burial or submersion.
The bottom of the Sacred Cenote is coated with a layer of that pigment that is four metres deep in some places.
We have trouble believing that amount of dye residue could have come solely from the sacrifice of artifacts and people, but it’s clear the Maya were definitely a bit on the religious side.
WATCH BELOW: BIG SINKHOLE CLOSES HIGHWAY, BEAVERS ARE TO BLAME
The Big Hole of Kimberley, South Africa
Here’s where we get into holes in the ground made by human hands. An awful, awful LOT of hands, in the case of the Big Hole in Kimberley, South Africa:
Image Source: Rudolph Botha/Wikimedia Commons
That huge and pretty-looking abyss was made with the tools, toil and sweat of 50,000 miners in 19th Century working conditions. By the time they were done, it was 500 m wide and 240 m deep, one of the largest man-made holes ever constructed.
From 1871 to 1914, miners excavated 22.6 million tonnes of earth. After all that effort, only around 2.7 tonnes of diamonds were recovered, enough to fill three of these:
Image Source: Stefan Fussan/Wikimedia Commons
Still, that relatively tiny proportion still represents unimaginable wealth, and South African mining giant De Beers is still pulling the precious stones out of the old tailpipes even today.
Incidentally, South Africa holds claim to another crown: The deepest mine on Earth.
One shaft at the TauTona mine, also known as Western Deep Levels, was sunk in the 1950s to a staggeringly deep 2 km - and as of the 2010s, it’s at 3.9 km.
It’s so deep, the conditions are a little Stygian – the mine needs an elaborate cooling system to bring the 55oC conditions down to a somewhat more manageable but still lousy 28oC, so employees can be forgiven if they think their jobs are a little hellish.
The Kola Borehole, Russia
For Stygian conditions, though, your best bet is, surprisingly, one of the coldest countries on Earth.
Image Source: Andre Belozeroff/Wikimedia Commons
That headgear up above is part of the Kola Superdeep Borehole complex, also known as “that one place where the Soviet Union tried to drill to the centre of the Earth.”
Okay, that’s an exaggeration: The Soviets were just trying to drill as deep as they could, and though their efforts fell well short of our planet’s deepest depth, they still made it a respectable 12,262 m.
It remains the deepest artificially drilled place on Earth, boring into rocks believed to be 2.7 billion years old. Though it may have begun as a Cold War race, it actually produced some interesting discoveries – like near-boiling water trapped underground, and flows of gas.
If you’ve heard of this at all, though, there’s a good chance it’s as part of one of those myths you occasionally hear about scientists somewhere in the world drilling down into an actual subterranean hell.
You can read the entertaining, and thoroughly debunked, theory on Snopes.com.
As for the real-life borehole, it was shut down due to lack of funding. But the infrastructure is still there. See this:
Image Source: Rakot13/Wikimedia Commons
That’s supposedly the welded-shut surface of the borehole. So if you stand on that thing, there’s a heck of a drop beneath you.
The Money Pit, Oak Island, Nova Scotia
The only Canadian entry on this list is also easily the weirdest: A supposedly man-made pit dug deep into the surface of Nova Scotia’s Oak Island.
It all started when three boys unearthed what they thought to be evidence of a deep pit and, hungry for treasure, began to dig.
They made it 30 metres down – and when they came back the next morning to keep going, they found the hole filled with 20 metres of seawater, and no amount of bailing could bring the water levels down.
This was 1795, so all the digging was done with 18th Century technology, but what they found was interesting – if the accounts are to be believed, they found several wooden platforms spaced at 10 feet intervals, as well as coconut fibre mats.
They, and the many, many other hunters who came after them, found artifacts like chests, parchment, some concrete, even a slab that was written in a cryptic language that, when “translated,” promised 2 million pounds another 40 feet down.
There’ve been stop-and-start searches for more than two hundred years now, involving hundreds of people and six fatalities (yes, people actually died trying to find out what's at the bottom).
The flooding is seriously believed by many to be caused by man-made underwater tunnels, while the actual treasure has been speculated to be pirate booty left by Blackbeard or Captain Kidd, the Holy Grail, Templar treasure, the lost secrets of Shakespeare, a Freemason conspiracy or Bigfoot’s secret summer getaway (We only made up the last one. The rest are all actual theories that have been proposed).
The bad news is, it’s probably just a sinkhole, with bits and pieces of Indigenous and colonial artifacts washed in by rains and floods (happens a lot, actually), and the treasure seekers are only seeing what they want to see based on sources more than a century old (also, the “translation” of the mysterious slab is probably bogus).
We like to think it really was dug by Blackbeard or whoever – and at the bottom is a big pile of nothing, left behind by someone with a plausible claim to being the biggest troll in history.
The Cave of Swallows is deep enough for base jumping
Moving on from centuries-old maybe-treasures to the wonders of the natural world, we’d like you to take a look at this video of people hurling themselves into the abyss:
Mexico's Cave of Swallows boasts the second deepest entrance drop in the world, allowing daredevils several seconds of freefall before pulling their chutes. It's faster than abseiling, who can make the 376-metre descend in about 20 minutes, and another 40 minutes to get back topside, using clamps (according to this caving site).
While you’re down there, try to avoid stepping on the scorpions, centipedes and legions of other creepy-crawlies that live in an environment featuring metres-deep fields of guano. The toxic air is so thick down there, anyone intending to actually explore the three-football-field wide floor is supposed to take a breath mask, or risk coming down with a fungal lung infection.
But even before it became an extreme sports Mecca, the cave attracted onlookers eager to glimpse the thick flocks of birds (mostly white collared swifts and green parakeets) that swarm in and out of the cave at dawn and dusk.
There are thousands upon thousands of them, even after running the gauntlet of the occasional bird of prey that loiters above the sinkhole hoping for an easy meal.
The downside of the cave’s growing popularity: Increasing tourism has been great for the local economy, but it's believed to be disturbing the birds, so more restrictions have gradually been placed on would-be adventurers.
Xiaozhai Tiankeng is actually a sinkhole WITHIN another sinkhole
If a sinkhole ever does open up under your property, you can rest assured that it almost certainly won’t be as big as China’s Xiaozhai Tiankeng, the largest sinkhole on Earth.
Image: Brookqi/Wikimedia Commons
What you’re seeing up there is actually a sinkhole in another even larger sinkhole, together making up a drop of around 662 m at the deepest.
It took more than 100,000 years for the elements to cut the hole this deep, and while nearby locals knew about it for centuries, it was “rediscovered” by surveyors in 1994.
Since then, of course, it’s a haven for tourists. If you look carefully at the pic above, you can just see the faint line of a staircase along the vertical wall of the lower sinkhole. It’s too far to see, but it’s made up of around 2,800 steps in total.
That’s an awful long way to walk, so if you like, you can take the shortcut, like these base jumpers:
The hole is so far across, they have to go along a cable to reach a point where they can drop directly into the lower sinkhole. And when that first jumper lets go of the cable around 30 seconds in, watch how much freefall time he has before he has to pull his chute. Looks to us like around 10 seconds.
And unlike Mexico’s Cave of Swallows, there’s no semi-toxic, bug-ridden guano pit waiting for him, but a thriving forest ecosystem, with more than 1,200 species of plant and rare animal species like the vulnerable clouded leopard.
“Tiankeng,” incidentally, means “Heavenly Pit” or “Sky Hole.” They named it well.
Three small holes lead down into the giant Majlis al Jinn
Except for three relatively small holes, the Majlis al Jinn in the Gulf state of Oman is completely closed off from the sky.
We wouldn’t have known about it had a pair of married geologists not wondered about said holes in aerial photographs, and trekked through the wastes to investigate.
So upon shimmying into what seemed to be just a series of wide-ish crevasses like this...
Image: Wikimedia Commons
…They ended up finding, to what we can only imagine was their incredible surprise and elation, that they opened up into this:
Image: Wikimedia Commons
The Majlis al Jinn – the “meeting place of the Jinn,” spiritual beings popularly known to western dwellers as “genies” – was the second largest underground cavern in the world when those intrepid geologists stumbled upon it (of course it was known to locals since forever). It’s since dropped to around ninth place, but it’s still spectacular, at 120 m deep and 310 metres at its longest.
It seems those three relatively small holes let in just enough sun and moonlight to create the impression of an eerie subterranean world, so it’s not surprising that, as usual, spelunkers and extreme sports enthusiasts began to flock to it.
The result? The Omani government closed the cave to the public in 2008, citing high profile, but illegal base jumping stunts by Red Bull and other corporations as being damaging to the site.
Red Bull, at least, countered that it was all above board, since their particular 2007 dive, with noted daredevil Felix Baumgartner, had been well advertised and known to Omani media, and that Baumgartner’s team included experts that helped minimize the impact.
Regardless of what the truth is, the cave remains closed for now, although the Omani tourism ministry says they’re working on re-opening the cave with more tourist-friendly access paths and attractions.
We can’t wait.
Mexico's Cave of Crystals is unbelievable (and dangerous)
No Genies in this cave beneath a mine in Mexico, but you’d be forgiven for wondering whether you should look over your shoulder to find Superman sternly demanding what you’re doing in his Fortress of Solitude.
You might need to be super-human to make it through the Cave of Crystals, though. The cave, which is kept drained of water by mine pumps, is around 58oC, with 100 per cent humidity.
Those conditions were key to forming those incredible gypsum crystal pillars (some of them are 11 m long) when the cavern was filled with mineral-rich water, but the thick air is filled with the same minerals – a serious danger to the lungs of explorers, who have to wear breathing apparatus.
The cavern’s days may be numbered, since the surrounding mine will close eventually and the pumps keeping the chamber dry and accessible will be shut down, but geologists say the cavern may be one of many such in the region.
Hopefully future explorers will turn up another beautiful work of natural art just like it.