There are many dangerous places covered on the channel, the most obvious of which are the caves with their claustrophobia inducing squeezes and deep water filled tunnels.

But the cave in this video is different.

It has none of those, and yet it might be the single deadliest cave on Earth.

These are some of the most dangerous places on Earth, and as always, for your discretion is advised.

Roughly five years ago, for a time, the world stood still.

Airport's empty, cities dimmed, loved ones were separated, holidays were skipped, and plans were put on hold.

For those who fell ill or lost someone who did.

The pain was deep, but the global pandemic was more than just a global health crisis.

Behind the scenes, scientists began issuing a new kind of warning that this might not be the end of it.

This is because pandemics don't just come out of nowhere.

Often they come from hidden places where humans and wildlife meet under the wrong circumstances, like in caves, forests, and wet markets.

They start in blood, saliva, and even dust.

And one of the most alarming candidates for the next outbreak isn't a distant lab or bustling urban center Instead, it's in a cave on the slopes of an ancient volcano in the green highlands of East Africa.

That place is known as Katoum Cave, dubbed by some as the most dangerous place on Earth.

If you've followed the channel for a while, you've probably heard at least one of the cave disasters.

But this is not one of those typical cave stories.

Instead, Katum Cave is something that can and very well may affect all of us one day, whether we've sworn off entering a cave or not.

The cave's entrance is hidden behind a waterfall that spills down from Mount Elgin, but it's no ordinary geological feature.

It wasn't carved by wind or water like a normal cave.

Instead, it was carved by elephants.

For centuries and maybe even millennia, animals have gone into its darkness in search of salt.

They do it blindly, night after night, stumbling through pitch black quarters in a single file.

Actual savannah elephants literally transform into clumsy miners, bumping their heads in the low ceilings and scraping at the walls with their tusks.

They chip awa at the rock like ancient quarry workers chewing the loosen rocks and even swallowing them whole.

Over time, these efforts have reshaped the cave itself.

Walls that were once smooth are now scratched and marked by generations of animals passing along a strange but vital ritual.

Katoumb Cave is one of five so called elephant caves on Mount Elgin, but it's by far the largest, so vast, in fact, that an entire herd can fit inside it at once.

And it isn't just elephants that go there.

Buffalo, bushbuck, antelope, hyenas and even leopards come to Katomb for the same reason, which is the promise of minerals buried deep in the mountain.

The mountain itself is an extinct shield volcano, but what remains beneath the surface is a vault of minerals like calcium, magnesium and sodium leach from ancient pyroclastic rock, and in a region where the rainfall is plentiful and vegetation is lush but nutrient poor, these salts are precious.

Pregnant elephants in particular crave them, and so they come night after night, bringing their calves and passing along the knowledge.

At first glance, this is kind of enchant It's like a hidden cathedral of natural history, buzzing with wildlife.

But Katomb Cave attracts far more than just outside animals.

Its walls are also alive with bats Egyptian fru bats, mostly along with smaller insectivre species.

Deeper within, they cling shoulders shoulder along a stone so densely packed that it's impossible to see where one bet ends and the next be ends.

Every inch of the upper walls and ceilings is coated in wings and fur, and the deeper you go, the lauder it gets, until the chirps echo like static from a radio, and then below them the floor is slick with guano.

This is a greenish sludge near the entrance from the fruit bats, and then darker black and deposits deeper in This cakes the rocks, soaks the crevices, and it fills the air with a sharp, acrid tang.

For the animals who make the pilgrimage nightly, this is all just part of the journey.

But for human visitors, especially those who don't know what they're breathing in, this place holds dangers far more serious than slipping on damp stone.

Deep inside the cave, there's a crevasse that splits the floor to form an invisible trap of swords.

Young elephants unfamiliar with tear have stumbled into it and never come out.

Their bones are set to light at the bottom, which in itself is disturbing enough.

But there's something more insidious than that.

Inside Katoumb Cave.

All that guano is by far the most dangerous thing you can encounter, because inside it viruses live, breed, and multiply.

Every night, a thousand microscopic interactions take place in the darkness, and one of them might be the spark that changes all of our lives.

That's why virologists come to Katum Cave, not for the scenery or for the elephants, but because something inside kills people, and no one exactly knows why.

In nineteen eighty, a French engineer named Charles Manette walked into Katum Cave.

What exactly he did there was unclear.

He might have simply explored.

Maybe he touched the walls or paused to admire the bats clinging to the ceiling.

Maybe he lingered too long in the iguana, rich air, breathing in the caves, in visible toxins.

Whatever it was, he walked out of the cave alive and never knew what he brought out with him.

Seven days later, Charles became violently ill.

It started with headaches, fatigue, and muscle aches, followed by a fever, vomiting and bleeding.

His condition then worsened rapidly, spiraling far beyond the scope of any ordinary illness.

He was then rushed to a hospital in Nairobi, where doctors fought to stabilize him, but his condition worsened.

When he finally crashed and his body gave out.

One of his physicians, doctor m Masoke, attempted to resustate him.

During this though, Charles vomited, projecting a fine mist of infected bodily fluid into the air, and the doctrinhiled it.

Shortly afterward, Charles lost his fight as his internal organs had liquefied and his connective tissue broke down.

This occurred so rapidly that, as one account later described, his face seemed to sag from the bone.

It was as though his body had begun to melt from the inside out.

Just more than a week later, doctor Musoki also began to show the same symptoms, but unlike Charles, he survived and from his blood doctors were able to isolate the virus causing it.

This was determined to be a cousin of Ebola, equally terrifying and completely new to them.

They would call it the Marburg virus after a nineteen sixty seven outbreak in Germany where lad workers were infected by monkeys imported from Uganda, but this strain was different, it was deadlier.

In nineteen eighty seventy, a Danish boy named Raven was vacationing in Kenya with his family and visited Katum Cave.

Three days later, he too became violently ill, and despite nearly two weeks of intensive care, he died in the hospital.

His strain of the virus was similar to the one that killed Charles, but was genetically distinct enough to earn its own name, the Raven virus, in honor of the boys sucumb to it.

This meant there were two confirmed deaths years apart, both traced back to the same place, and this was enough to set off alarm bells in the scientific community.

Katum Cave was now a threat something in it was harboring a virus, something capable of spilling into the human population without warning, and the question wasn't just what was causing it, but why it was happening there and nowhere else.

This was also enough to catch the attention of the US Army Medical Research Institute of Infectious Diseases.

If something inside the cave could kill so quickly and gruesomely, and if it could leap from animals to humans without warning, then it was also a potential weapon of mass puction.

So in the late nineteen eighties, a team was sent to Katum Cave, covered heads to protective suits and wearing respirators.

Their mission was to find the natural host of the Marber virus, identify the species carrying it, isolate the virus in a lab, learn how it works, and contain it before it jumped again.

They would go into trap fruit, bats and sectivorous bats, rodents, ticks, and birds.

Every animal they could catch they sampled, They swamped surfaces, collected guano, and took environmental readings, but nothing conclusive came up.

The virus seemed to have vanished, or at least was hiding too well defined, so the military eventually packed up and left no closer to an answer than when they arrived.

In two thousand and seven, nearly two decades later, a break came, though not in katumb Cave.

Instead, miners and Uganda and Gabon began falling ill with some sort of fever.

In response, new expeditions were launched into African gold and iron mines that harbored colonies of Egyptian fruit bats, the same species within Katum.

This time scientists found what they were looking for.

Within those bats, they isolated live Marber virus.

Egyptian fruit bats were confirmed carriers of the virus, and they were roosting by the thousands inside Katoma Cave.

Later that year, researchers once again returned to Mount Elgin with better tools.

They then captured and tested bats from Katum again, and this time they found it.

It was then learned that while the virus doesn't spread through the air in the traditional sense like a cold or flu, it can potentially be inhaled in another form.

The batguano code in the cave walls kicked up as dust may have carried viral particles.

So you didn't need to be bitten, you just need to breathe in the wrong place, the wrong time for Charles and Ravin, that may have been exactly what happened.

And what makes it all more unsettling is that there are likely more viruses in that cave than just Marbourg.

But quickly, let's get into what makes Marburg so dangerous and threatening in the first place.

It's something known as a philovirus, belonging to the same nightmare's family as a bola, and according to the World Health Organization, it's one of the most virulent pathogens known to science, capable of killing up to eighty eight percent of those infects after first contact.

The incubation period can stutch from two two days to three weeks, and symptoms appear like a common virus high fever, chills, headache, and body aches, but the resemblance ends there.

Within days, the virus begins a systemic attack on the body.

It ravages the gastrointestinal tract, causing severe diarrhea, vomiting, and cramping, and then it moves to the vascular system.

Blood vessels then begin to break down and the body's ability to clop fails.

Bleeding can occur from the gums, eyes, ears, nose, and even the skin and In the worst cases, blood leaks into the internal organs themselves.

As a result, patients develop expressionless faces, sunken eyes, and a ghostly complexion as shock sets in.

What makes marbur even more dangerous, though, is how it spreads.

Unlike airborne viruses, it doesn't travel through a cougher sneeze.

It needs bodily fluids like blood, saliva, vomit, or urine, so doctor's nurses treating patients without proper protective gear are at extreme risk.

Even handling the belongings of an infected person like towels, clothing, or bedding can be enough to pass it on.

So while it's not quite as infectious as something airborne, it could plausibly spread rapidly in the right conditions, like for example, if Marburg were to emerge in a crowded urban area undiagnosed, even for a few days, the consequences could be catastrophic.

And what's worse than that is that for now treatment is only supportive as in fluids, oxygen, and painkillers.

It's basically damage control, and even then survival is far from guaranteed.

In twenty twenty one, as the pandemic was still prevalent, across the globe.

The World Health Organization issued a warning that Marburg is prone to epidemic and the potential is still there.

The right person in the wrong place, and the virus could escape containment.

Maybe what's most worrisome, though, is that Katomb Cave still opens the public.

Tourists like the trails of Mount Elgin, and school groups peer into the mouth cave, snapping photos from beneath the waterfall.

Adventurous travelers even step into the darkness with head lamps and guides, marveling at the elephant tusk marks etched into the stone.

It's likely that few even know but the threat that lies beneath their feet or above their heads, and even fewer know that the very walls around them may still harbor the virus that more or less dissolve Charles from the inside out, and as with Marburg, their st ill potential for other passagens that are just not known about yet.

But for all its deadly potential, Katoom Cave remains the crown jewel of Mount Elgon National Park and its strange beauty continues to pull people in.

There's a certain kind of peace that settles over the Yorkshire countryside that feels old, ancient even, and Nestled within those hills.

Carving a path through the heart of the Dales is the River Whar.

It's a gentle flowing river at first, the kind of river that seems to just meander.

It's shallow and wide, and its waters flows slowly over stones worn smooth by time, and beside thickets of wildflowers and green rolling fields.

It's the kind of place that makes you want to take a few deep, relaxing breaths.

The name Wharf is thought to come from the Old Norse word hever fi, meaning a bend or a turn, and the river lives up to this name.

It twists its way through North Yorkshire and for centuries it's shaped land and the people who live near, Running for sixty five miles from its source high and the moors to its junction with another river.

Along the way, it passes old abbeys, stone bridges and villages with names pulled straight at a foot folklore.

But also like many old things in England, the River Wharf holds mysteries and legends.

While much of the river rolls wide and easy, there's one stretch that is remarkably different.

Just a few minutes walk upstream from the ruins of Bolden Abbey, the river narrows dramatically.

It actually pinches in so tightly that it no longer looks like a river at all.

It more resembles a harmless little stream between mossy rocks.

Here, though, the river wharf transforms into something else entirely, something that has pulled people under and never let them go.

Locals call it the Bolden Strid, and it's earned every bit of its sinister reputation.

As surprising as it might seem, this is a place that kills at an unbelievable rate if you're unfortunate enough to find yourself within it.

And again from the banks, it really doesn't look like much.

It's just a narrow ribbon of water flowing between rocks and a wooded glen.

Even its name, the strid, sounds kind of playful in some places.

It's also only six feet or two meters wide, almost as if daring you to leap across it.

And many have, and that's how the story often begins.

But step closer to the water's edge and you'll feel a subtle wrongness.

There's almost a quiet roar beneath the surface.

Where the water doesn't so much flow as it convulses.

What looks like a gently moving river is actually something far more dangerous, because a portion of the river wharf is literally turned on its side.

To understand why the street is so unforgiving, you have to look beneath the surface.

Most rivers flow with a certain transparency.

You can see their shallow sections engage their depth, But the strid is different.

What looks narrow and manageable is actually a large vertical shaft crammed with millions of gallons of water forced through a space it was never meant to fit.

This is because when the river wharf approaches the strait, it undergoes a sudden transformation.

It goes from a broad ninety foot or thirty meters wide channel to being squeezed into a fissure barely six feet across.

But the river doesn't slow down to accommodate this change.

Instead, it accelerates violently.

The water flows into the sandstone channel at frightening speed, driving downward and twisting through a subtraining labyrinth of tunnels, crevices, and voids carved over millennia.

And these aren't neat predictable pathways either.

They're cho it could jagged an entirely hidden from view.

No one has ever fully mapped them, and no devor has even descended to explore them, because none would survive the attempt.

The tight channel creates immense hydraulic pressure that crushes, twists, and traps anything it grabs against its many unseen stone outcroppings.

The banks are also actually more like overhanging ledges that stretch out thinly over the water below.

If someone falls in, they're apparently almost immediately sucked into the bank itself, or even worse, into the depths of the laventh below.

They'd then be thrown against the submerged rocks with all the force of the immense current.

Even if this doesn't knock them on immediately, they're totally disoriented.

There's no way to tell which direction is up, where the air is, or how deep the water truly goes, And all the while the current keeps pulling down below.

The river behaves almost like it's trying to tear itself apart.

Now, although that's the real danger of the street, it's not just the speed of the water, it's also the depth.

The depth is officially unmeasured, although Estimus suggests that it plunges to at least two hundred feet or sixty five meters.

This was a figure recently determined by a YouTuber who wanted to get to the literal bottom of the mystery.

If that number is accurate, it also makes it one of the deepest bodies of water in the entire country.

And as a result of all of this, locals hold that the strid has a staggering one hundred percent fatality rate for those who enter it, either willingly or otherwise, and in fact, even without any intention of getting in, just a little too close can be the beginning of the end because even the bank's treacherous, they're slick with moss, so one wrong step is all it takes.

And again, the rocks you can see above the surface only the tip of the structure beneath them.

The caves, overhangs and ledges create perfect traps and chambers that catch debris, branches, and even bodies, and that is exactly what happens.

People fall in, but they don't often come out, at least not alive anyway.

Some are never even found at all, and those that are have been carried miles downstream with their remains battered beyond recognition.

The water in the strait simply obliterates anything that comes in contact with and those who end up in it are slammed against the stone again and again in total darkness until the current is finished with them.

To be clear, there are no second chances.

Yet, there's no scrambling out, swimming to safety, or being lucky enough to grab onto the rocks along the banks.

It is, without the slightest hint of exaggeration, one of the most dangerous stretches of water on Earth, and it's been that way for centuries.

Then, in stark contrast, next to it is a soft wooded trail where tourists walk, take photos and admire the mossy stones.

A sign nearby offers a polite yet stern warning, reading quote, the strid is dangerous, and his claim lives in the past.

Please stand well back and beware slippery rocks.

And again ask the locals, and they tell you nobody who falls into the strid comes out alive.

That's just the pattern, it seems, and it's a legend that comes from centuries of disappearances and grim recoveries.

According to local legend, its first known victim was a noble child named William de Romilly, son of Lady Alice de Romilly, who owned the land the strid resides on.

The story goes at an eleven fifty two, young William attempted to leap from one bank of the Strid to the other.

His greyhound dog, sensing something was wrong, refused to follow, but William jumped anyway and the river took him.

His body was never recovered.

Afterward, Lady Alice, stricken with grief, is said to have donated the land around the river to the monks of Bolton Priory in her son's memory.

To this day, the priory's ruins still stand downstream from the Strid, and since then more stories have accumulated.

Centuries after the supposed death of William in nineteen thirty four, the strid claimed another light, that of Arthur Reginald Smith, a sixty three year old watercolor artist.

Arthur was well known for painting natural landscapes and had likely come across the air in search of the perfect composition, but instead he drowned trying to cross the strid.

But maybe the most tragic story occurred in August of nineteen ninety eight.

Barry and Lynne Colette were just two days into their honeymoon in Yorkshire, newly married, happy and strolling along the river wharf in Bolton Abbey.

They had no idea what was coming.

A flash flood triggered by heavy rain over night caused the river to rise five feet in less than a minute.

It's not known for sure how the couple ended up in the street, but police believed they were caught completely off guard by the rising waters and swept away.

A hiker named Desmond, who was walking nearby with his family it later described seeing Barry's body surface briefly before being sucked back under.

It took six days to recover Lynde's body near the weir in Addington, but Barry's wasn't found till October, two months later, and when it was, it was ten miles or sixteen clumbers downstream.

More recently, in twenty ten, and eight year old was near the Strid celebrating his birthday.

He was spending the day with a large group of family members along the banks when he and his older brother were hopping across some stones near a picnic area just upstream from the Strid.

It's a common enough thing for kids to do in the area, but the boy slipped.

A fast acting passerby managed to snag him and grab one but the current leading into the strid was stronger than he was and the boy slipped out of his hands.

It then pulled him under the water almost instantly.

A rescue effort involving twenty eight people got underway and the boy's body was found three hours later, long dead before anyone had a chance to save him.

And these are just the stores that are known about.

There are others whose names are loss of time, hikers who've disappeared, children who strayed too close to the edge, and bodies that were never found.

The strid doesn't leave much behind it, yet this does little to nothing to deserve anyone from coming to witness it.

It's one of the most picturesque places in all of Yorkshire, and the trail through the Stridwood is blowed by hikers, dog walkers, photographers and families with strollers.

It's not some isolated, foreboding place.

This is a maintained path with information plaques, stone walls and picnic spots.

The woods around it are so quiet and inviting that it's easy to forget that this stretch of river is actually a killer decorated moss.

So despite its well documented dangerous the strait continues to attract visitors by the hundreds every day, drawn in by its natural beauty and ominous reputation