From oblivion to buried treasure: Seven weird/scary/awesome holes

Daniel Martins
Digital Reporter

Monday, November 25, 2013, 11:28 AM -

If you've clicked through to this article, chances are it's because you're one of our many readers who, for whatever reason, are simply fascinated by stories that involve the ground opening up and swallowing something.

Sinkholes in particular are super popular on our website, including one in Florida earlier this month, and another in Montreal that nearly devoured a backhoe.

So we looked into it, and we came up with seven holes, natural or man-made, that stand out because they are super fascinating, stunningly beautiful, or plain terrifying.

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).

IMAGE: J.C. Winkler/Flickr

IMAGE: J.C. Winkler/Flickr

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 (it's facing lawsuits from residents, although several have accepted buyouts). 

Making matters worse: Toxic gas was detected near several of the area's homes, and while this source says 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:

Gualemala sinkhole 2010 1

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.

Gualemala sinkhole 2010 2

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: USGS

Image: USGS

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 feet 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 (the hole is about midway down the reef in this orbital shot).

Image: NASA

Image: NASA

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 last week. 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: Salhedine/Wikimedia Commons

Image: Salhedine/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 Mayan's were definitely a bit on the religious side.

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: Irene2005/WC

Image: Irene2005/WC

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: Stefan Fussan/Wikimedia Commons

Image: 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 55C conditions down to a somewhat more manageable but still lousy 28C, 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: Andre Belozeroff/Wikimedia Commons

Image: 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. 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

As for the real-life borehole, it was shut down due to lack of funding. But the infrastructure is still there. See this:

Image: Rakot12/Wikimedia Commons

Image: Rakot12/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 90 feet down – and when they came back the next morning to keep going, they found the hole filled with 60 feet 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 native 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).

Even the so-called flood tunnels are probably naturally occurring features (if they even exist), and skeptics are pretty quick to debunk most of the myth (you can still totally go visit if you want).

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.

THERE'S A PART II! And you can read it here.

Six man-made features you can see from space
Five major features that were hugely different thousands of years ago
Seven weird things we found under the sea

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