Places You Should Never Ever Swim

Here are some dangerous places and bodies of water where you should never swim!

September 12, 2023・

19 min read

Not all bodies of water are made for swimming. Some of the lakes, rivers, and pools may look inviting, but taking a dip in them might be the last thing you ever do! From pretty pools that are actually brimming with acid, to flooded holes that are impossible to escape, let’s dive into some swimming spots you should approach with caution and others that you shouldn’t approach at all!

Lake Natron

Even though it sounds like something out of a fairy tale, Tanzania has a 490-square-mile body of water that can turn living things to stone. Lake Natron is located in a part of Tanzania that’s so hot that it loses most of its water to evaporation, which leaves salty, mineral-rich remnants to crust over the lake bed. Consequently, salt-loving microorganisms that sport a deep red pigment thrive on what the water leaves behind.

However, the water that does remain is so saturated with salt that migratory birds, who stop for a refreshing bird bath, suddenly find themselves coated in salt crystals! Once they calcify, those salty layers trap the poor creatures in a matter of minutes, mummifying them alive. It's not exactly stone, but close enough! However, that’s not even the worst part.

The sodium and mineral-rich bedrock makes Lake Natron’s environment strongly alkaline, meaning the water there has a pH of 10 on an average day, and a pH of 12 when the waters reach a scalding 140°F! So, at its worst, taking a dip in the lake would be like swimming through hot bleach, leaving you with serious alkaline burns.

It is something a group of wildlife photographers horrifying experienced firsthand back in 2007. As they were flying over the lake, their helicopter pilot became disoriented and crashed! The chemicals in the water immediately began irritating their eyes, practically blinding them while slowly burning their skin.

But, miraculously, they managed to brave the pain and scramble 2 miles across the shallow waters to the nearest solid ground. Luckily, they all made a full recovery. But if they had crashed much further out, or if it had been an even hotter day, it could have ended fatally!

Jacob's Well

In the hot Texas summertime, kids near Wimberley love nothing more than playing in a local creek, one which leads to a spring called Jacob’s Well. Springs like it are usually small, and can present a fun photo opportunity if they’re just the right depth!

But the 12 ft diameter mouth of the spring looks weirdly huge like it’s been punched into the bedrock! And with a 30 ft plunge straight down, it seems like a perfect place to practice a cannon ball or 6! But something dark lurks at the bottom of the well, something that’s claimed the lives of many people who have dived down too far.

Jacob’s Well is a karstic spring that’s part of an underwater cave system. Past the 30 ft main chamber, the cavern continues down to a series of tunnels and chambers separated by narrow shafts. That is until it reaches an average depth of 120 ft, with adjoining caves and tunnels stretching out more than 4500 ft! And that’s just the caves that’ve been explored!

The intricate system is something that’s attracted cave divers and free divers from all over the world, and herein lies the main danger of swimming in Jacob’s Well. Some of the entrances to other tunnels are so narrow that divers have to remove their oxygen tanks to squeeze through them! All it takes is one fumble, and their oxygen tanks could be lost to the dark cavernous stretches below.

More than a dozen divers have lost their lives in Jacob’s Well that way. If that wasn’t scary enough, back in 2015, Diego Adame was freediving in the cave, which is diving without the use of an oxygen tank, relying instead on lung capacity and pure willpower alone! He’d sunk down some 100 ft, squeezing through impossibly small gaps, when all of a sudden he lost a flipper.

Terrified that he wouldn’t be able to make it back to the surface in time without it, he cut away the weight belt he’d used to help him sink and made a desperate scramble for the mouth. Miraculously, Diego made it back up to the surface in the nick of time. But if he’d been down slightly deeper, or hadn’t been able to cut his belt away, it might have been a very different story.

The Eagle's Nest

Located on the Floridian coast, The Eagle’s Nest is a flooded sinkhole that, at a glance, looks like a secret pool hidden perfectly from the rest of the world. Sometimes its waters are completely clear, other times it’s practically black, dyed by naturally occurring pigments called tannins from the surrounding vegetation.

But no matter what the water looks like on the surface, once you head under, the danger is turned up to 11. Because it is just the entrance to a huge network of caves and tunnels submerged beneath, some as deep as 310 ft, stretching out more than 16,000 ft a mile, all in the pitch black.

It’s a popular spot with cave divers, who take some sort of psychopathic joy in the idea of traveling underground, underwater, while practically blind. What’s more, because some either incredibly brave or utterly deranged part of them want to push the boundaries of exploration, they try to map previously uncharted caves and tunnels.

The issue is, it’s easy to get turned around and lost in there, especially in the pitch black when all the rocks around you look the same in the torchlight. As such, some over-ambitious divers and swimmers have become so lost they’ve never made it back to the surface.

Since 1981, at least 13 divers have succumbed to the utterly horrifying fate. It’s gotten so bad that Caution signs have been installed in the cave to try and dissuade overeager swimmers from swimming further on and getting lost!

Blue Lagoon

In the UK, another deceptively beautiful-looking lake can be found in a pit dug into the Derbyshire countryside. It used to have beautiful blue waters and was aptly named Blue Lagoon.

In 2013, and then again in 2020, the local council dyed the waters black to try and dissuade eager locals from taking a dive in it. But why? Because, despite the lagoon part of its name, it’s actually situated in an old limestone quarry, which, after it was disused in 1952 was eventually left to gather rainwater.

As the surrounding limestone rocks leached calcite crystals into the water, the water gradually became that inviting turquoise color, but it also gave the lagoon a strong alkaline pH of 11.3. Considering ammonia has a pH of 11.5, and bleach is about 12, swimming is the last thing you want to do in those waters.

At that strength, the water causes skin irritation, stomach problems, and even chemical burns, but it wasn’t enough to stop people from taking a dip, especially during lockdown! Despite mounds of trash in the water, dead animals, and an impossible-to-miss warning sign, people can still be found risking a paddle in the pit. Public pools don’t have the best reputation, but swimming in bleach surrounded by garbage doesn’t exactly sound like an upgrade.

Pink Lake Hillier

A lot of open bodies of water can look enticing thanks to their incredible coloring, though they’re not always shades of blue. Lake Hillier in Australia, for example, is famous for its bright pink waters! Found right on the coast of the country’s Middle Island, the 2000 ft long lake is separated from the ocean by a thin strip of land, and looks so vividly pink that it almost seems fake!

The super-salty waters get that hue from a mixture of red-colored bacteria and algae that reside in it. Both contain red carotenoids; pigments that help protect them from extreme environments, such as the high amount of salt. But for all the high salt content, the waters aren’t dangerous unless ingested in large quantities.

El Chichón Crater Lake

Over on the other side of the world, there’s another colorful lake I’m sure plenty of influencers would love to get a picture of them swimming in. From a glance, the lake's water looks like made from liquid emeralds. But before any influencers start planning which filter they’re gonna use, it isn’t a lake you can use for a photoshoot.

For a start, it’s located in the crater of an active volcano in Mexico, known as El Chichón. Following its catastrophic eruption in 1982, the crater of the volcano today is some 420 ft deep, though the depth of the lake itself varies. A series of superheated springs channel groundwater from the crater floor into the lake, but those waters aren’t just dangerous because they’re hot.

Dissolved into them are deadly volcanic gasses from the magma beneath, such as Sulphur dioxide, hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. These don’t just give the lake its glowing green color, they also turn the water acidic.

After the eruption in 1982, the lake that formed in the crater the following year had a pH of 0.5 for perspective, that’s the same as battery acid, but the Sulphuric components make it even more deadly. So, if an Instagram background is what you’re looking for, you should search elsewhere unless you want your followers to watch your hospital recovery story!

Grand Prismatic Spring of Yellowstone

Not all deadly bodies of water are just one color, as proven by The Grand Prismatic Spring of Yellowstone National Park. Located in the Midway Geyser basin, it is the third largest natural hot spring in the entire world, measuring 370 ft in diameter! That means, from end to end, it’s more than double the length of an Olympic swimming pool!

The bedrock sports huge concentric circles of vibrant blues, greens, yellows, and oranges, making it look like a magic portal rather than a pool! But those aren’t magic. They’re down to the geothermally heated water that erupts from the center of the spring, which can reach a near-boiling 189°F.

When the water spreads out, it cools, allowing rings of different bacteria that thrive at temperatures to develop, ranging from 131 to 189°F. That’s still seriously hot! Like, third-degree burns hot. Though burns are the least of your worries in the area.

Back in 2016, a tourist was visiting these Yellowstone Springs when he and his sister, despite all the warning signs, decided to go hiking in a restricted area. They planned to take a dip in a hot pool away from prying public eyes, but as he was checking the temperature of the water, he accidentally slipped and fell!

He scrambled desperately, but couldn’t get out. His sister tried to pull him out, but with the waters here reaching a scalding 199°F, she suffered serious burns and couldn’t help! Because they’d deviated from the path, help arrived far too late.

A thunderstorm called off an attempt to retrieve his remains, and they made plans to return the next day. But because the water in the area is also slightly acidic, combined with the intense heat, when they returned the next day, his body had dissolved.

Strokkur Geyser

So, we’ve established that going off route and trying to take a dip in naturally hot pools of water definitely isn’t a good idea. But that message hasn’t reached every risk-taking skinny dipper out there, so here's another more extreme example of a spring that could quite literally kill you if you decided to step foot in it.

To discuss our next topic, we need to head over to Iceland, a nation famous for its volcanically active landscape and geothermally heated water sources. It’s there we find a pretty small, innocuous-looking pool located beside the Hvítá River. It’s all very serene, but around every 10 minutes, something disturbs the peace:

It isn't an ordinary pool. It’s actually the Strokkur Geyser, one of the most active fountain-type geysers in the world. Geysers like this are made from flooded systems of tube-like holes and linked chambers that run deep into the Earth’s crust.

Magma then heats the water at the closest end of the tube until it begins to boil, and as it does, it rises up into the chamber, where it begins to steam and turn into a gas. This gas then shoots towards the surface, forcing the water around it to jet out at incredible speed!

As fun as it might look to dive in and shoot up on nature’s own slingshot ride, it isn't all fun and games. The power of the steam forces the water out to heights of up to 130 ft, meaning it has the power to launch something within it to around the height of a 10-story building.

On top of that, the water in this geyser can reach a spicy 464°F! So, making the dumb decision to jump in here would leave you with two options: boil to death, or fall to your death. The third option is to stay well away from it, but that decision is up to you!

Naruto Whirlpools

If there are any anime fans out there, the next twisted body of water is definitely for you. Over in Japan, the Naruto Strait is a channel between Naruto in Tokushima and Awaji Island in Hyōgo. It may be less than a mile long, but it connects the Pacific Ocean to the inland sea, and when the tides rise and fall twice a day, something amazing happens.

Because such a huge amount of water is pushed in or dragged out of the area, the tide creates a water level difference of up to 5 ft between the two seas. And because the strait is so narrow, the water rushing through here at up to 12 mph creates a series of massive whirlpools, circling some 66 ft in diameter. Those are known as the Naruto whirlpools!

They directly inspired the name for narutomaki, a spiral-styled fishcake, which in turn inspired the name for Naruto Uzumaki, one of the most popular anime characters out there, whose name literally translates to “Naruto Spiral”.

While the whirlpools themselves aren’t strong enough to be dangerous to boats, lone swimmers are cautioned to avoid the straits as they can be quickly overpowered by the currents.

Case in point, back in 2014, a daredevil underwater photographer intent on capturing footage of a comparatively small whirlpool in Cornwall, UK, didn’t make it back to the surface. Though it appeared small, the current creating it had the power to drag the photographer under and hold him there which, without any breathing apparatus, proved fatal.

Lake Berryessa

Open swimming in wild waters can seem like a great idea on a hot day, but if you decide to go paddling in a reservoir, you’ll have more to worry about than forgetting your sunscreen! Natural lakes and man-made reservoirs can look very similar, though reservoirs are generally built for flood control, and as such they have a few in-built elements that make them incredibly dangerous.

Take Lake Berryessa in California for example, which is held up by the mighty 304 ft tall Monticello dam. The reservoir stretches back more than 15 ½ miles, and when full, can be up to 275 ft deep.

If heavy rain threatens to exceed this level and spill over the dam though, Berryessa’s secret weapon gets to work. The image below reveals an open mouth spillway more than 72 ft in diameter, which is locally known as the Glory Hole.

The glory hole channels water down a 200 ft drop to the base of the dam, where the diameter shrinks down to about 8 ft wide. With the design, the spillway can drain a maximum of 48,000 cubic feet of water, roughly 359,000 gallons per second. That’s a little under half the water in an entire Olympic swimming pool, meaning it generates one heck of a current when it’s in use.

But despite warnings, and even a cordoned-off section, it’s not enough to stop swimmers from trying their luck. Back in 1997, after heavy rains, a woman decided to test her mettle by ignoring all the warnings and swimming close to the Glory Hole.

No match for the current, she was quickly dragged into the mouth. Realizing her mistake, she clawed at the edge and managed to hold on! But the Glory Hole is located miles from the nearest available help, and so after 20 minutes, she lost her grip and was dragged down.

But despite the severity of stories like this, they’re not enough to dissuade some people, like the two anglers in the footage below at Ladybower reservoir in the UK, who seem to have a death wish!

Unlike Berryessa, Ladybower has not one, but two bellmouth spillways affectionately nicknamed plugholes. Each one is 78 ft in diameter with a 66 ft drop channel that deposits water back into the river on the other side of the dam through a grill. They may not have the same drop length as Berryessa, but with those staggered stone steps I’d argue that being dragged down into the watery maw would hurt a lot more.

The firm that manages the reservoir allows people to fish, boat, and swim out on it, but advises everyone to steer clear of the spillways, a memo both those idiotic anglers missed, apparently! Luckily, no fatalities have been recorded regarding either of the plugholes so far.

Kimberley Mine, The Big Hole

With a lot of these lakes, it can be hard to tell at first glance what exactly makes them dangerous. But you don’t have that problem with South Africa’s aptly named Big Hole. Once known as the Kimberley Mine, it used to be an open-pit diamond mine.

When work started there back in 1871, digging progressed until the pit itself was more than 1500 ft wide and 790 ft deep, meaning it was 4/5ths as deep as the Chrysler Building was tall. As it got deeper, the only way miners could get in and out was by a series of death-defying Aerial Trams which led down to the workable surface of the mine.

But by 1914, after 22 million tons of rock had been excavated along with more than 3 tons of diamonds, work on the mine ceased. The water pumps installed at the bottom to keep the hole from flooding were removed, and water naturally filled it up to the waterline. Part of the hole was filled in, leaving the final depth of it today at some 705 ft deep, where 134 ft of water sits at the bottom of the Big Hole.

Surrounded by a sheer rock face, the walls are practically impossible to scale, as one unlucky dog found out back in 2013. The poor pooch had accidentally fallen into the hole, and for several days swam desperately from one side to another, hoping to find a way out amidst the sheer rockfaces.

Eventually, passersby spotted him before throwing down some food and alerting emergency services. But the workers were hesitant to help. The walls of the mine are incredibly unstable, and they didn’t have ropes long enough to lower someone in.

They made multiple, unsuccessful attempts to get the dog out, but it wasn’t until the 8th day, when a team of 7 people was sent down into the pit with rope and pulley systems in place that they were eventually able to hoist the dog out! So, unless you’re very good at treading water and then climbing up a partially sheer rockface for 570 ft without any help, I wouldn’t recommend diving into that death trap!

Hanakapiai Beach

The Hanakapiai Beach, located on the Hawaiian island of Kauai, will certainly mesmerize you. Bright blue waters, golden sands, blue skies, it’s a textbook-perfect beach, ideal for swimming. But you will see people paddling in a tiny pool on the beach instead of swimming in the ocean. Why do they do that? Because they’re smart, that’s why!

For all its scenic surroundings, it is one of the deadliest beaches in the world, with many people, speculated to be close to 100 having been swept out to sea over the years, never to return. Makeshift signs warn of the danger, but tourists still don’t listen! After all, it doesn’t look all that dangerous at first.

But unlike most beaches along the Kauai coast, there’s no major barrier reef before it. So, there’s nothing stopping the strong ocean currents from breaking along the ledge of the beach with their full force, rolling onto it, and dragging unsuspecting tourists out into the blue. Plus, there are no lifeguards there, so if you’re swept out to sea, you’re out there on your own!

Berkeley Pit

If you were to visit Butte, a city in Montana, you’d notice that it looks like any other typical American city that is until you spot the mile-long, half-mile-wide pit lurking at the edge of it! At roughly 1,780 ft deep, filled with a reddish brown liquid that can only be described as ominous, it is called the Berkeley Pit.

It was an open pit copper mine dug out back in the 1950s, but it was closed just 30 years later in 1982 after its profitability hit rock bottom. They shut off the pumps keeping the ground water at bay, and the pit was left to flood.

However, the water that filled it up had leeched chemicals and metals from the surrounding rock, like arsenic, cadmium, zinc, and Sulphuric acid, which gave it that worrying color though that’s not all.

A while later in 1995, a migrating flock of 342 snow geese flew down and rested in the lake to avoid a squall. But little did they know the lake had a pH of 2.5, meaning it was acidic! While it was only about as acidic as lemon juice, the poor birds were all found lifeless the next day, completely covered in burn sores!

The shocking incident spurred Montana to treat the water in the pit, but it’s still incredibly toxic, so much so the Berkeley Pit Waterfowl Protection Program has been established to deter any birds from resting there!

And you know what they say, if birds won’t take to the water, then neither should you. Okay, literally no one has ever said that, but the message is still the same: Don’t go swimming in the big toxic pit!

I hope you were amazed at these dangerous places that you should never swim! Thanks for reading.