00:00It was 1905. A 13-year-old boy named Ben Sands grabs his lantern and slips into the Craighead
00:07Caverns in Sweetwater, Tennessee, a place he already knew like the back of his hand,
00:12but that day felt different. He was in the mood for a little more adventure,
00:17so he left the main trail behind and went deeper into the shadows.
00:22That's when our brave teen decided to squeeze into a narrow, muddy tunnel,
00:27barely as wide as a bicycle tire. He crawled for what felt like forever.
00:32Then, after about 40 feet, he finally popped out the other side and couldn't believe what was
00:38happening. He had water up to his knees. Yep, he was standing in the middle of a massive
00:44underground lake. The chamber was so huge, the light from his lantern barely reached the walls.
00:50Then, he had a great idea. He started tossing mud balls into the darkness as far as he could,
00:56just to test the ground ahead. All he heard in return was splash, splash, splash. It was all
01:02water. What Ben had discovered would later be named the Lost Sea, which is considered America's
01:09largest underground lake. It's also the second largest non-glacial subterranean lake in the
01:15world. The only one bigger is Dragon's Breath Cave, hidden on private land in Namibia.
01:22The underground lake in Craighead Caverns is so massive and mysterious, we haven't fully explored
01:29it. Thanks to top-notch equipment, divers have discovered more than 13 acres of water-filled
01:34rooms beneath the surface. But the visible part of the Lost Sea stretches only about four acres.
01:42One time, a brave diver entered one of the submerged chambers with a sonar device in hand.
01:47This kind of equipment works by sending out sound pulses underwater. When those sound waves hit
01:53something, they bounce back. Then, the device measures how long it takes for the echo to return
01:59and calculates how far away the object is. So, he was confident he could map the whole thing using sonar.
02:06But he also played it safe. He hugged the wall the entire time, the only way to make sure he'd find his
02:12way back. As he took surroundings in every direction, the results came back the same. Nothing but more water.
02:21To this day, no one has found the end of the lake, but they're not done yet. Each expedition reveals new
02:27chambers, new tunnels, and new mysteries. The funny part is, Craighead Caverns was already a well-known spot
02:34long before Ben stumbled across the Long Sea. And over the years, this cave has had some pretty unusual
02:41and kinda eccentric uses.
02:45The first people we know who used the cave were the Cherokee. The upper chambers served as a meeting
02:51place for their councils. And we know that because a wide range of Native American artifacts, including
02:57pottery, arrowheads, and jewelry, have been found in one of the rooms. Then, between 1939 and 1940, the
03:05cavern was turned into a mushroom farm. A few years later, in 1947, someone decided to build a wooden
03:13floor right inside the cave. That's when the underground nightclub known as the Cavern Tavern was born.
03:20And here's another fun fact. One of the cave's earliest visitors wasn't a person at all. It was a giant
03:26jaguar. It made its way deep into the cave, about 20,000 years ago, and apparently got lost in the
03:33darkness. It wandered for days before falling into a crevice, far from any light. Some of its bones were
03:41found in 1939, and today, they're on display at the American Museum of Natural History in New York.
03:48But I suppose nothing that's ever happened in the cave quite compares to what lies deeper inside.
03:54If you're feeling brave enough to explore its depths, you can actually take a boat tour across its
03:59underwater lake. That's right, there are excursion boats inside the cave, all powered by electric
04:05motors. It is probably a dark, cold, and strangely peaceful journey. And just below the boat, you'll see
04:13some big rainbow trout swimming around. They weren't always there. People actually brought them in and
04:19released them into the underground lake. And according to visitors, the guides explained that
04:23it was all part of a bigger plan. They wanted to see if the fish would find an exit and reveal a hidden
04:29tunnel to another body of water. But the fish stayed put. So now, visitors have something else to look at
04:36during the ride. And since there's no natural food in the cave, the trout have to be fed by hand every
04:43single day. Guides also mentioned that one of the most fascinating features of the caverns isn't the
04:48lake or the trout. It's a crystalline structure known as anthodytes, also called cave flowers. These
04:55are fragile, spiky clusters, and they are rare. Really rare.
05:00Now, here is a question. If Ben Sands discovered a lost sea out of nowhere, does that mean we could
05:07still find something similar? Well, yes. There are probably still many underground bodies of water
05:14hidden around the world. In 2016, for example, a massive reservoir of water was discovered deep
05:20beneath the Utturunko volcano located in the Andes. But it's not like a calm, friendly lake. The water is
05:27dissolved into partially molten rock, so it's stunningly hot. We're talking about a temperature
05:33close to 1,830 degrees Fahrenheit. Then, in 2021, scientists found a huge thermal lake inside a cave
05:44in southern Albania. And in 2024, they returned to the same spot with more advanced measurement equipment.
05:51They found that the lake measures 454 feet long and 138 feet wide. That pretty much confirmed it is
05:59the biggest hidden lake of its kind we know about. Also, in 2024, a group of workers from a travel
06:06agency was exploring Thung Cave in Vietnam, when they suddenly came across a mysterious lake,
06:12hidden way down in a part of the cave that hardly anyone ever sees.
06:17It's water reflects a transparent emerald or greenish color, making it look unbelievably beautiful.
06:24This spot will probably be open to tourism very soon.
06:30Alright, finding hidden lakes inside caves or beneath volcanoes is one thing,
06:35but finding a hidden ocean inside the Earth, that is a whole different story. And believe it or not,
06:42it actually happened not long ago. But you can't swim in its waters, for two big reasons. First,
06:49it's hidden about 400 miles underground. And second, the water isn't in liquid form like a normal sea.
06:58Instead, it's trapped inside solid rocks. Sounds strange, but let me explain. Back in 2014,
07:05researchers found deep pockets of magma located around 400 miles beneath North America. And that's
07:12a pretty strong sign there's water down there. But how? Down there, scientists discovered a mineral
07:19called ringwoodite, which only forms under extremely high pressure, the kind you would find deep within
07:26the Earth's mantle. And inside the structure of ringwoodite, they found water, not in puddles or pools,
07:33but trapped inside the mineral itself. Ringwoodite acts like a sponge, holding water within its crystal
07:40structure. And when scientists ran the numbers, they realized something staggering. The amount of
07:46water trapped in this mineral could be three times greater than all the oceans on Earth combined. And
07:52that is huge. Not just in size, but the actual discovery is huge, because it might confirm a theory
07:59that's been around for decades. That a massive reservoir of water exists deep beneath Earth's crust.
08:07Geologists believe this deep reservoir plays a key role in Earth's water cycle. It might be
08:12responsible for volcanic activity, the movement of tectonic plates, and even how water first appeared
08:18on the planet's surface. Instead of arriving on comets or asteroids, Earth's water might have always been
08:25here, slowly seeping out over billions of years from deep underground.
08:34That's it for today. So hey, if you pacified your curiosity, then give the video a like and share it
08:39with your friends. Or if you want more, just click on these videos and stay on the Bright Side!
Comments