The Horrifying Incidents in This Bottomless Cave

Hello everyone, and welcome back to Scary Interesting. In this video, we're going to go over two extremely strange dive sites. These locations are unlike any other covered on the channel before, and they each have several disturbing incidents, adding to their already creepy reputation.

As always, viewer discretion is advised. [intro music] One look at the Fosse Dionne in France's Burgundy region, and it's easy to see that this spring is unlike anything that's ever been covered on the channel before. It's a karst spring, which is similar to other caves, but beyond that, from the surface, it's completely unique.

The Fosse Dionne isn't some remote body of water, miles and miles away from civilization. It's also not located in a natural preserve surrounded by forests and hiking trails. Instead, the Fosse Dionne, which translates to "Divine Pit", is right in the center of the French town of Tonnerre, and its surroundings are anything but natural.

There's a narrow stream that runs right through the town before opening up into a perfectly circular spring surrounded by Renaissance era homes and castles that look down into it. The surface walls of the spring are also manmade with stone later in the 18th century that form a perfect circle around the water. From the edge of the stone wall above the pit, the water is a clear blue and green except for one side where the blue becomes much deeper, clearly indicating the entrance to its massive cave.

What isn't immediately apparent from looks alone, however, are the mysteries the Fosse Dionne keeps secret in its dark and winding underground chambers and passageways. Part of this aura can be attributed to legends that have been passed down from generations. The first time the Fosse Dionne makes an appearance in any literature, is in a text written in the year 659, which tells a story of a 7th century monk.

The monk apparently heard of the Fosse Dionne and what the locals said lurked beneath the waters. At the time, the sinkhole was used by people of the town for drinking, bathing, and cooking, and there were stories of creatures living beneath the surface. One of those rumors was of a cryptid known as a basilisk, which is a half lizard and half rooster.

Upon learning of this creature, the monk traveled to the town with the purpose of ridding the community of the beast. During the Middle Ages, the Fosse Dionne had another origin story as well. Supposedly, on a dark night, a young girl hurried through town on her way home and came to a swampy area.

At this moment, she realized she was being followed as she heard footsteps behind her. When she ran, though, so did whoever was following her, and the same when she slowed down. Her fear eventually boiled over and she bolted as fast as she could, but her pursuer was faster and caught up to her to the point that she could feel his breath on the back of her neck.

When she was sure she'd been caught, the girl whispered to the Virgin Mary and begged for help. Suddenly, the night almost became day with the vision of a robed woman bathed in light. Then, before whatever was chasing the girl fully caught up, the Virgin Mary laid her cloak down on the ground, and the Fosse Dionne appeared.

The girl then ran into the arms of Mary, and the two descended into the safety of the spring. Later in the Middle Ages, the Fosse Dionne took on a new reputation as a portal to the underworld, and as such, more local lore began to develop. One story even tells of a young boy seeing the devil himself in the form of a black knight riding into the spring and disappear into the depths.

Now, whether or not you believe these legends, there are plenty of more practical aspects to the Fosse Dionne that make the spring intriguing, particularly to divers. For one thing, no one is really sure of the source of the waters. It is known that it's partially fed by the rain that trickles down from the surrounding hills.

In a 20th century study using dye tracing, determined that at least some of the flow comes from an underground section of the Lane River. Where the rest of the water comes from though is anyone's guess, despite the local government's efforts to uncover the mystery. In addition to the source of the water, Tonnerre officials have also been hiring divers for generations, all the way back to the 19th century to explore what lies beneath the basin, with limited success.

Until 1908, regular dives were performed, but due to the equipment available at the time, no one ever ventured beyond the immediate basin. This all changed in the middle of the 20th century when the first exploration with tanks was performed in 1955, although the divers on that expedition also didn't make it terribly far from the entrance. In 1962, with significant advancements in diving equipment and capabilities, a small team of divers finally made it past the Fosse Dionne's extremely narrow entryway.

The group was still only able to descend to about 92 feet, or 28 meters, but it marked significant progress to that point. One year later, the same group came together in Tonnerre, hoping to push further into the underground chambers, but something went horribly wrong during the dive, and two of them lost their lives. Around this same time, another dive was performed that was successful by the Le Guen brothers, who managed to explore all the way to 1,181 feet, or 360 meters.

This meant that the cave was suddenly 10 times bigger than previously thought, and the end still hadn't been reached. And it would take another 10 years for that mark to be exceeded by diver P. Jolivet, who traveled another 33 feet, or 10 meters further.

Then in 1974, two divers were hired to navigate as much of the underwater cave as possible beyond that length, but neither of them ever returned. It's unclear if their bodies have ever even been found. Two decades later, another diver was hired in 1996 to explore the Fosse Dionne, but he too lost his life in the attempt.

From then on, diving at the spring was banned by the local government until 2019. That year, another diver named Pierre-Eric Deseigne was granted permission and reached the same point as Jolivet, only to be turned back. So, to this day, no one has made it past that mark, and rumors persist that the Fosse Dionne is bottomless.

Now, while there are no details available on what exactly happened to the divers who died during their attempts to explore the cave, there is plenty of information available on what exactly makes Fosse Dionne so dangerous. At the top of the list is flow rate. On an average day, the spring's current flows at 82 gallons, or 311 liters per second, but during heavy rains and floods, the current can reach upwards of 793 gallons, or 3,000 liters per second.

But even the average flow rate adds to the danger inside the Fosse Dionne, because there are several extremely tight restrictions that concentrate the current. This means that divers have to use a lot of strength and energy to swim. At its entryway as well, which can be seen from the surface, the opening to the underground labyrinth is about 8 feet, or 2.

5 meters wide, but that quickly narrows as the tunnel descents to around 128 feet, or 39 meters, almost like a funnel squeezing down to a point. And this is where divers will encounter two extremely tight restrictions. The first of which is only 2.

5 by 1. 3 feet wide. And yes, just 1.

3 feet wide. I highly recommend you grab a tape measure and see if your shoulders even fit through that width. For divers, in order to get through this claustrophobic portion of the tunnel, they have to remove their air tanks and push them through ahead of them.

They also have to do this without ripping their regulator from their mouths, and in most cases, they're up against almost zero visibility conditions since such a tight restriction makes it impossible not to strip the silt along the cave's floor, walls, and ceiling. And even more incredibly, just beyond this restriction is a second that's even smaller. As if to underscore just how dangerous this area is, each of the divers who was recovered who lost their lives in the Fosse Dionne, was found lifeless in this exact area.

And for those who successfully pushed past these two early restrictions, they're soon reminded why it's been such a challenge to go any further than what's been reached. This is because, the tunnel beneath the Fosse Dionne doesn't just descend from the entryway. Instead, its depth undulates.

Once past the first two restrictions, divers ascend at nearly a vertical angle, almost to surface level. Because of this, they have to perform decompression stops during that ascent before continuing on to avoid decompression sickness. Once they reach the top of this ascent, divers have to descend all the way to 98 feet, or 30 meters again before ascending back to near surface level.

This again requires decompression stops, but at this point, they're 591 feet, or 180 meters from the entrance. It's only after this point that the cave continues in a descending fashion to the furthest point reached. And if you're wondering why this is such a big deal, it comes down to two things: time and gas.

Because of the number of decompression stops that are required to navigate well into the cave, divers who plan to go further than anyone before would have to bring an unreasonable number of air tanks with different gas mixtures. And considering divers have to remove their air tanks and push them through the entryway restrictions just to get into the main portion of the cave, it's just not a feasible pursuit. As a result, the Fosse Dionne remains today with closely guarded secrets that will likely never be brought to light.

Located in the foothills of the Alps, Lake Constance in Germany, lies right near the country's border with Austria and Switzerland, and at 39 miles, or 63 kilometers long, it's one of Europe's largest sources of fresh water. In fact, behind Lake Geneva, it's the second largest by water volume and third largest in terms of area. It was formed by the Rhine Glacier during the last glacial period, 10,000 years ago, and is split into two sections—an upper lake, and then a lower lake—and then connecting the two sides is a short river.

The earliest reference to the lake has been traced back to the Romans of 43 AD, and archaeological finds in the area suggest the presence of Mesolithic period hunter and gatherers between 8000 and 5500 BC. Today, though, Lake Constance and the surrounding area are a popular destination with everything from swimming to boating, and even diving. Depending on where you are on the lake, however, there's something beneath the surface.

This is known ominously as Teufelstisch, which translates to "Devil's Table". Sitting just off the banks of the town of Walhausen, the Devil's Table is a geologic formation known as a rock needle In the United States, these are common in places like the Grand Canyon, and they can often rise for hundreds of feet. They're created over millions of years as result of windblown sand.

And rock needles can take on a variety of shapes, although the one thing that usually remains consistent with them are their steep cliffs. Underwater, the Devil's Table in Lake Constance is no different except for the fact that it's completely submerged in water. This makes it a prime location for divers, but not just anyone can hop in the water to take a peek at this massive formation.

Today, diving at Devil's Table is strictly regulated, as the site is infamously known in diving circles for being challenging. There are several reasons for this, but let's start with what Devil's Table actually looks like. About 6 feet, or 2 meters below the surface in this area of the lake is a wide plateau, which you might confuse for the bottom of the lake if not for the sheer cliffs at the edge of this plateau that drop dramatically to as much as 295 feet, or 90 meters.

And wall diving, unlike cave diving, also doesn't occur with an overhead environment, so no matter how deep a diver goes, the surface is always just above them. And because this is the case, there's no certification required to participate in wall diving so it's an activity that attracts divers of all experience levels. It sounds simple enough to do—just follow the rock wall down to a target depth, admire the formations along the way, and then you begin your ascent.

But there's actually a lot of trouble a diver can get into while wall diving, and especially in Lake Constance. The lake is known for having large, vertical underwater waves which act like a random strong current. So imagine you're swimming along, and then out of nowhere, you're suddenly, and violently pulled upward or downward by this current.

This would obviously be terrifying. And in addition to that, which is already terrifying enough, divers who frequent the lake say there are three things you have to be comfortable with in order to successfully dive the lake, which are depth, darkness, and cold. And because there is plenty of all three at Devil's Table, it can be easy to get disoriented once you're deeper than the sunlight the surface can reach.

To avoid this, it's recommended that divers set a compass in the direction of the cliff face upon reaching it, so that if they lose sight of the wall at any point during the dive, they can just swim according to the compass and eventually find their way back. As you might imagine, those who aren't seasoned divers can easily panic by losing sight of the cliff face. In one second, you might be next to this large wall, which is acting as your guide, but then in the next second, you're in a dark nothingness with nothing to guide you.

So because of all of these factors, to dive Devil's Table today, divers have to get a permit. And in order to be issued one, divers have to prove that they performed at least 40 dives within the previous 12 months, and at least 10 of those dives must have taken place at Lake Constance to a depth of at least 66 feet, or 20 meters. This restriction has been in place since 1979, and for good reason.

Devil's Table was the site of several dives with tragic endings beginning in 1977. On May 7th that year, divers Wolfgang and Eberhard, both 27 years old, left their hometown early in the morning, heading for Walhausen. The two were experienced divers, and both were members of a diving club, so diving Devil's Table was to be a leisurely activity for both of them.

The two men each had double compressed tanks that held around 4,000 liters of air, which was good enough for about 40 minutes of diving. Once they arrived at the lake, they had a friend waiting on shore, and told him that they'd be back at the surface in around half an hour. With that, the two descended and began exploring Devil's Table.

However, about 90 minutes later, so one full hour after they were expected back, the friend on shore realized something wasn't quite right. He then suited up and entered the water to look for the two divers but found nothing. The lake water police were then notified about the incident several hours later, and soon after, the local media became aware and arrived at the scene to find water police managing a recovery operation.

Tragically, when speaking with the operations leader, reporters were told that it was already far too late to save the two men. Just after 6 PM, the first two rescue divers entered the water and searched to a depth of around 230 feet, or 70 meters, which is considerable and requires a handful of decompression stops on the ascent to perform safely. After 45 minutes, a second team entered the water as the first team was ascending.

The second team also searched for about 45 minutes before beginning their ascent. A third team then entered the water, which was made up of several divers from this first attempt. If this third try didn't turn up the bodies of the two lost divers, the plan was to start using underwater cameras to search for them, as the depth made for physically exhausting dives for rescuers.

The third group consisted of six men—none of which were able to locate Wolfgang or Eberhard— so around 8:30 PM, they began ascending. At the surface, it was around this time when the support team noticed that the rising bubbles from below had dissipated, and this raised the alarm that the third team might be in some sort of trouble. All the support divers then leapt into the water and started to descend, hoping to find the other members of the rescue team.

When they did, though, they found four of them were working frantically to get two others who had lost consciousness to the surface before it was too late. Unfortunately, it was an effort that would be in vain as the two rescue divers were dead long before they reached the surface. During an autopsy on the two rescue divers, it was determined that they were actually suffering from decompression sickness.

It seemed that they hadn't fully recovered from their first dive when they joined the third team that day, and the bodies of Wolfgang and Eberhard have never been recovered. Immediately after the tragedy in 1977, diving at Devil's Table was banned completely and it remained that way until the ban was lifted in 1978 at the urging of the German Sport Diving Association. It wouldn't be long after this that tragedy would occur again at the now-notorious diving site.

Around 3 PM on July 8th, 1979, 35-year-old Ernst and 28-year-old Fritz entered the water near Devil's Table, as their wives watched from a boat on the surface. Ernst was an experienced diver who had more than 10 years of diving under his belt, and while Fritz had considerably less experience, he had been diving near Devil's Table before without issue. Both of the men entered the water with about 45 minutes' worth of air, but by 4 PM, neither of the men had surfaced.

Their wives then contacted the Lake Constance Water Police, who began a search of the shoreline, which turned up nothing. Then, later that evening, an underwater search got underway. However, well after darkness had fallen over the Alps, the dive was called off and the plan was to resume the next day.

But before that could happen, the district administrator reinstituted the diving ban at Devil's Table that night, likely with the 1977 tragedy in the back of his mind. So unfortunately, no search was conducted the next day, and a specialized team of underwater experts had to be brought in to resume the effort with underwater cameras. More than a week later, the bodies of Ernst and Fritz were located more than 150 feet away from the Devil's Table rock wall, at a depth of around 295 feet.

When they were brought to the surface, it was discovered that their air tanks were completely empty, meaning the pair had drowned during the dive. How this could have happened became apparent on further inspection of what the men were wearing that day. Despite Ernst being a much more experienced diver, who would've known better, both men were wearing belts filled with upwards of 18 pounds, or 8 kilograms of lead to aid in their descent.

Diving experts believe this is way more weight than necessary, and the problem was compounded by how they were wearing the belts. Normally, weight belts are worn outside the straps of any other gear a diver might wear, and they're normally fastened around the waist with quick-release buckles. By doing this, if a diver suddenly finds themselves dropping too quickly or too far, they can undo the buckle and allow the weight belt to fall right off.

However, Ernst and Fritz wore their weight belts underneath the rest of their equipment, and neither were fastened with quick-release buckles. This could mean the men suffered a horrifying ending. The dive suits that divers wear are positively buoyant; this makes it easy to float.

However, the equipment they wear adds some weight already. Then as they descend with the pressure at depth, this reduces the buoyancy of the dive suit. This means that if they went too deep without realizing it, they could have made themselves negatively buoyant, causing them to begin to sink if they weren't actively swimming upward.

Without the ability to release their weight, this could have easily led to a rapid, uncontrolled descent to the bottom. And if they were conscious for this, they would have known the entire time where they were going without any way to prevent it from happening. With the diving ban at Devil's Table, the area went more than a decade without any incident, but as time went on, restrictions began to relax again, and the current permit system was instituted.

On May 10th, 1991, eight divers secured the necessary permits, having satisfied all the criteria, and made their way to Walhausen. The descent occurred without any issue, but after the divers surfaced, they realized one of them was missing. A search for the diver got underway immediately, but it only took 15 minutes for him to be found, floating lifeless on the surface of the lake.

According to his dive computer, he had gone much deeper than he planned for and likely lost consciousness on the ascent. A little more than two years later, a similar incident occurred when two divers, one of which was a diving instructor for the previous two years, entered the waters around Devil's Table. According to the police, the less experienced diver suffered some sort of issue and lost consciousness.

The dive instructor then apparently rushed over to assist, but neither of the divers ever surfaced. Their bodies were eventually located and recovered. In addition to the number of fatalities at the lake, Devil's Table has also been the site of some very close calls.

On April 1st, 1997, several permanent divers at Devil's Table were enjoying a routine dive, when something extremely strange happened. One of the divers, who was only identified as "Matze", felt a strong, brief pull downward. When the divers looked below them, they saw a dark shadow that appeared to be 13 feet, or 4 meters long.

As it continued to ascend, it became clear that it was a massive and curious catfish. Suddenly, the fish grabbed ahold of Matze's foot and started dragging him toward the bottom. Matze then grabbed ahold of the hand of one of the other divers and pulled as hard as it could to try to free his leg from the catfish's mouth, but to no avail.

So thinking fast, he pulled out a knife from his dive belt and stabbed the catfish in the head. This obviously caused the catfish's mouth to open, releasing Matze's foot from its grasp. The catfish then sank back into the depths as Matze, and he and his dive mates initiated an emergency ascent, and all would survive the incident.

Now, obviously, this incident doesn't really have much to do with Devil's Table itself, but it is still ironic that it happened nearby. Thankfully, though, other than that, since the permit restrictions went into effect, only two divers have lost their lives at Devil's Table. But, despite this, due to its long history, the reputation persists to this day.

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