- [Narrator] As
temperatures start to climb, there's no better way to cool down than to take a dip in the pool. But be careful, because not all bodies of
water are made for swimming. Some of these 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 you shouldn't approach at all. (upbeat music) Bleach Bath. What do you know about Tanzania? That it's in Africa? That it's home to some amazing wildlife? That it has a
490-square-mile body of water which can turn living things to stone? Wait, what was that last one? That sounds like something
out of a fairy tale. But believe me, it's real. This is Lake Natron, located in part of Tanzania that's so hot, it loses most of its water to evaporation. This leaves salty, mineral-rich remnants to crust over the lake bed with salt-loving microorganisms that sport a deep red pigment thriving 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 bath suddenly find themselves
coated in salt crystals. Once they calcify, these salty layers trap the poor creatures in a matter of minutes,
mummifying them alive. Okay, not exactly stone, but close enough. Though that's not even the worst part. The sodium and mineral-rich bedrock makes Lake Natron's environment
strongly alkaline, meaning the water here has
a pH of 10 on an average day and a pH of 12 when the waters reach a
scalding 140 degrees Fahrenheit. So at its worst, taking a dip in this lake would be like swimming through hot bleach, leaving you with serious alkaline burns. This is something a group
of wildlife photographers horrifyingly 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 two 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, this could have ended fatally. (fast-pacing music) Narrow Escape. 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 this are usually small and can present a fun
photo opportunity like this if they're just the right depth. But the 12-foot diameter mouth of this spring looks weirdly huge, like it's been punched into the bedrock. And with a 30-foot plunge straight down, it seems like a perfect place to practice a cannonball or six. 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. Not a monster, thank God,
at least as far as we know. You see Jacob's Well is a karstic spring that's part of an underwater cave system. Past the 30-foot 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 feet with adjoining caves and
tunnels stretching out more than 4,500 feet. And that's just the caves
that have been explored. This 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, 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 this way. And like 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 sunk down some 100 feet squeezing through impossibly small gaps when all of a sudden he lost a flipper. (Diego gulps) Terrified that he wouldn't be able to make it back to the surface in time, he cut away the weight belt
he'd used to help him sink and made a desperate move
to scramble for the mouth. (Diego gulps) Miraculously, Diego made
it back up to the surface in the nick of time. But if he'd been down even slightly deeper or hadn't been able to cut his belt away, it might've been a very different story. Did anyone else feel their heartbeat get a little faster there? Man, between being stuck
in an underwater cave or being boiled alive in a lake of bleach, I'm not sure which fate would be worse. What do you think? For the bleach bath, hit the Like button. For the narrow escape, hit Subscribe. All done? All right, great. Okay, deep breath. (man gasps) What watery nightmare have we got next? (fast-pacing music) The Underwater Labyrinth. Tell me something, how many times have you dived
into a pool, started swimming, and then gotten lost? Not a regular occurrence, I'd hope. But for those brave enough to step foot in the Eagle's Nest Sinkhole, it's a very real possibility. 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 this is just the entrance to a huge network of caves
and tunnels submerged beneath, some as deep as 310 feet
stretching out more than a mile, all in 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 wants 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 here, 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 never made it back to the surface. Since 1981, at least 13
divers have succumbed to this utterly horrifying fate. It's gotten so bad that signs like this one have
been installed in the cave to try and dissuade overeager swimmers from swimming farther on and getting lost. Well, no need to dissuade me, Florida, because luckily for you,
I am a massive coward. (fast-pacing music) Black and Blue. Over in the UK, another deceptively
beautiful-looking lake can be found in a pit dug into the
Derbyshire countryside. These are the beautiful blue waters of the aptly named Blue
Lagoon, or they used to be. 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? Well, 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. Because the surrounding
limestone rocks leached calcite crystals into the water, the waters gradually became
that inviting turquoise color, but 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 these waters. At that strength, the water causes skin
irritation, stomach problems, and even chemical burns. But this 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 this pit. I mean, I know public pools
don't have the best reputation, but swimming in bleach surrounded by garbage doesn't
exactly seem like an upgrade. (fast-pacing music) Yellowstone's Secret Weapon. Now, not all deadly bodies
of water are just one color, as proven by the Grand Prismatic
Spring of Yellowstone Park. Located in the Midway Geyser basin, this is the third largest
natural hot spring in the entire world, measuring
in at 370 feet 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 these 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 degrees Fahrenheit. When this water spreads out, it cools allowing rings
of different bacteria that thrive at different
temperatures to develop, ranging from 131 to
189 degrees Fahrenheit. That's still seriously hot,
like third-degree burns hot. Though burns are the least
of your worries in this area, back in 2016, a tourist was visiting
the Yellowstone Springs when he and his sister,
despite all the warning signs, decided to go hiking
into a restricted area. They planned to take a dip in a hot pool away from the prying public eyes. But as he was checking the
temperature of the hot 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 reaching a scalding 199 degrees Fahrenheit, she suffered serious
burns and couldn't help. Because they'd deviated from the path, help arrived far too late. A thunderstorm called off and attempts to retrieve his remains, and they made plans to
return the next day. But because the water in this
area is also slightly acidic, combined with the intense heat, when they returned the next day, his body had dissolved. Ugh, yeah. Think I'll just stick
to the regular hot tub. Thanks. (fast-pacing music) Hot And High. 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 I get a feeling that
message hasn't reached every risk-taking-skinny-dipper out there. So we're going to look at another more extreme
example of a spring that could literally kill you if you decided to step foot in it. For this, we need to head over to Iceland, a nation famous for its
volcanically active landscape and geothermally heated water sources. It's here we find a pretty
small, innocuous-looking pool located beside the Hvita River. It's all very serene, but around every 10 minutes,
something disturbs the peace. (water splashing) Whoa, this ain't no 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 gas. This gas then shoots towards the surface forcing the water around it to
jet out at incredible speed. Now, as fun as it might look to dive in and shoot up on nature's
own slingshot ride, it ain't all fun and games. The power of the steam
forces the water out to heights of up to 130 feet, meaning it has the power to
launch something within it around the height of a 10-storey building. On top of that, the water in this geyser can reach a spicy 464 degrees Fahrenheit. So making the dumb decision to jump in here would
leave you with two options, boil to death or fall to your death. I mean, the third option is
to stay well away from it, but I'll leave that decision up to you. (fast-pacing music) Whirlpool Worry. If there are any anime fans out there, this 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 Hyogo. 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 this area, the tide creates a water level difference of up to five feet between the two seas. And because the strait is so narrow, the water rushing through here at up to 12 miles per hour creates a series of massive whirlpools, circling some 66 feet in diameter. These are 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. Told you the anime nerds
would like this one. 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. So to all the ninja anime fans out there, unless you've mastered the
walk on water technique, I'd suggest using a boat. (fast-pacing music) Risky Reservoirs. 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 manmade
reservoirs can look very similar, though reservoirs are generally
built for flood control. And as such, they have
a few built-in elements that make them incredibly dangerous. Take Lake Berryessa in
California, for example, which is held up by the mighty
304-foot-tall Monticello Dam. The reservoir stretches
back more than 15.5 miles, and when full can be up to 275 feet deep. If heavy rain threatens
to exceed this level and spill over the dam though, Berryessa's secret weapon gets to work. This is an open mouth spillway more than 72 feet in diameter, which is locally known as the Glory Hole. Seriously, California? Seriously? Well, the glory hole channels
water down a 200-foot drop to the base of the dam where the diameter shrinks
down to about 28 feet wide. With this 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 try and 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 help. So after 20 minutes, she lost
her grip and was dragged down. Yeah, there ain't no
surviving an event like that. But despite the severity
of stories like this, they're not enough to
dissuade some people, like these two anglers 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 feet in diameter with a 66-foot drop channel that deposits water 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 this watery maw would
hurt a heck of a lot more. The firm that manages the
reservoir allows people to fish, boat, and swim 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. I, for one vote, we keep it that way by not swimming in bodies of water that have giant holes in them. (fast-pacing music) Big Hole. Now, 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 Kimberly Mine, it used to be an open-pit diamond mine. When work started here back in 1871, digging progressed
until the pit itself was more than 1,500 feet
wide and 790 feet deep, meaning it was four-fifths as deep as the Chrysler Building is 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 the water naturally
filled up to the waterline. Part of the hole was filled in leaving the final depth of it
today at some 705 feet deep, where 134 feet of water sit
at the bottom of the big hole. Surrounded by a sheer rockface, the walls are practically
impossible to scale, as one unlucky dog found out 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 passers-by 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 eighth day when a team of seven people
were sent down into the pit with a 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 feet without any help, I wouldn't recommend diving
into that death trap. (fast-pacing music) Life's a Beach. Whoa, would you just look at this place? Bright blue waters,
golden sands, blue skies, it's a textbook perfect beach
ideal for swimming, right? But wait, why are people
paddling in that tiny pool and not over enjoying the ocean? Because they're smart, that's why. You see, this is Hanakapiai Beach located on the Hawaiian island of Kauai. For all its scenic surroundings, this 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 this 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's 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 here. So if you're swept out to sea,
you're out there on your own. Err, remind me never to take
my water wings off ever again. (fast-pacing music) Colorful Caution. A lot of open bodies
of water 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 2,000-foot-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 water gets this hue from a mixture of red
colored bacterium 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. So it's an influencer's
pink-colored paradise, let's just hope they don't try
and drink it for the likes. Over on the other side of the world, there's another colorful lake. I'm pretty sure plenty
of influencers would love to get a picture of them swimming in. From a glance, it looks like those waters
are made from liquid emeralds. But before any influencers start planning which filter they're gonna use, this isn't a lake you can
use for a photo shoot. For a start, it's located in the crater of
an active volcano in Mexico, known as El Chichon. Following its catastrophic
eruption in 1982, the crater of the volcano
today is some 420 feet deep, though the depth of
the lake itself varies. A series of superheated springs channel groundwater from the
crater floor to the lake. But these waters aren't just
dangerous because they're hot. Dissolved into them are
deadly volcanic gases from the magma beneath, such as sulfur dioxide, hydrogen sulphide, hydrogen chloride, and hydrogen fluoride. These don't just give the
lake its glowing green color. They also turn the water
acidic, like very acidic. After the eruption in 1982, the lake that formed in the
crater the year following at a pH of 0.5. For perspective, that's
the same as battery acid. But the sulfuric components
make it even more deadly. So if an insta background
is what you're looking for, I'd search elsewhere, unless you want your followers to watch your hospital recovery story. (fast-pacing music) Big Pit. If you were to visit
Butte 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 feet deep, filled with a reddish-brown liquid that can only be described as ominous, this is 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 leached chemicals and metals from the surrounding rock, like arsenic, cadmium,
zinc, and sulfuric 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 that 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. (upbeat music) Well, after that, I don't think I'm gonna be
needing my speedos anytime soon. Did any of these horrifying bodies of water put you off swimming for life? Let me know down in the comments below. And as always, thanks for watching. (upbeat music continues)
