00:00Tunnels, metro, underground systems, and even secret passageways to the houses of the rich
00:05and famous.
00:06Why else do we need tunnels, you may wonder?
00:09To hide!
00:10Many cities have underground tunnels and even underground doppelgangers.
00:15Now let's make it clear, those passages are normally not connected, contrary to the
00:20popular rumor claiming that it was possible to get from Scotland to Turkey using underground
00:25passageways built around 5,000 years ago.
00:29I mean, it sounds insane even today, imagine building it back in the day!
00:36These tunnels have an official name, the Erdstahl Tunnels, and they were most likely built in
00:41the Middle Ages.
00:42However, we still don't have the exact information about the date.
00:47The highest concentration of those tunnels are in Bavaria, Germany, but there are many
00:52of them in Great Britain and France too.
00:56Erdstahl Tunnels, a unique type of earthen passage found globally, are characterized
01:01by their narrow, oval-shaped corridors and tight choke points, known as schlups, or slip-outs.
01:08Despite speculation, their purpose remains a mystery.
01:12However, some of those tunnels have fireplaces and even vents, which might mean those were
01:17used primarily for shelter.
01:21Going back to the Middle Ages, possibly as early as the 12th century, Erdstahl Tunnels
01:26lack archaeological signs and historical records, so it's not a surprise that there are many
01:32rumors about their use.
01:35Some scientists are sure those were storage spaces, though their narrowness makes this
01:40impractical.
01:42Another idea is that they provided hiding spots for farmers during tribal raids.
01:47However, their single entry point raises doubts about their effectiveness in evading threats.
01:54Now if you're feeling like Indiana Jones and want to venture into those tunnels, you're
01:58in luck.
01:59A few structures, like the Erdstahl-Rotkoblucken in Austria, welcome visitors to explore these
02:05enigmatic structures.
02:07Most of them are closed to the public eye, though.
02:11The origins of Erdstahl Tunnels remain largely unknown, just like their real functions.
02:16And if you think, hey, it's the 21st century here, we can study pretty much everything,
02:22well you're wrong.
02:23What makes these tunnels hard to study are the tight confines.
02:27Traditional surveying methods often prove inadequate in such spaces.
02:32To solve this problem, scientists use a handheld device that integrates an RGB camera, a gyroscope,
02:40and high-resolution depth sensors, allowing them to capture intricate details of the tunnels.
02:46They also use modern techniques like 3D surveying in hopes of uncovering the true origins and
02:51purposes of those tunnels.
02:54One hypothesis even suggests they may have been poorly conceived dwellings, abandoned
02:59when their inadequacies became apparent.
03:02Still, not everyone quite agrees with this idea.
03:07Other theories suggest they served spiritual purposes, while the most intriguing idea speculates
03:13that those tunnels may be remnants of extraterrestrial civilizations.
03:18Experts believe they may have been used for practical matters, such as granaries or hiding
03:22spots from looters.
03:25As we don't have exact info on who built it and when, it may be pretty much anyone.
03:31Even a sloth.
03:32Nope, I'm not a lunatic.
03:34Sloths can build giant tunnels.
03:37Check this out.
03:38In 2009, a farmer in southern Brazil was driving his tractor through a cornfield when it suddenly
03:45sank into the ground.
03:47He quickly discovered he had broken through the top of an underground tunnel.
03:51When researchers came to investigate, they found a tunnel around 6.5 feet high and the
03:57same 6.5 feet wide, extending about 50 feet long, right beneath the farmer's house.
04:04When they looked closer, they instantly saw deep claw marks on the walls.
04:09That was the proof the tunnel wasn't human made.
04:14So that thing the farmer uncovered was a megafauna paleoburrow, a prehistoric tunnel dug by ancient
04:20creatures like giant ground sloths or giant armadillos from over 10,000 years ago.
04:27I know, it's hard to imagine those beasts, but let me help you.
04:32Take a hamster.
04:33Now, increase it to the size of an elephant.
04:36Ah, don't forget, this 13-foot tall hamster could also walk on two legs.
04:42During their time, around 15 million to 10,000 years ago, many species of sloths and giant
04:48armadillos roamed the Americas, some even digging similar tunnels.
04:54Today, many of these tunnels are filled with sediment, though some remain clear, similar
05:00to the one the farmer discovered.
05:03This 2009 find sparked significant interest, leading to the discovery of over 1,500 paleoburrows
05:10across southern Brazil, making it the era with the highest concentration of such sites
05:15worldwide.
05:17But no one knows exactly why there are so many of them in southern Brazil.
05:22While some paleoburrows exist throughout South America, none have been found in North America,
05:28which is weird since those huge sloths roamed the entire continent.
05:34The exact purpose of these large tunnels remains a mystery, but scientists believe they may
05:39have served as nursing spaces, temperature regulation, or hibernation areas.
05:45Tunnels likely developed over centuries as successive generations of sloths and armadillos
05:50expanded them.
05:52Now, let's take a look at fugus.
05:55No, not the Japanese fatal delicacy, and no, not a town in New Guinea.
06:00To see them, we gotta travel to the UK.
06:03So fugus are underground structures too, but they don't look exactly like tunnels.
06:08They are dry stone structures.
06:13They look as if a cave had been decorated with stones from the inside.
06:17There are only around 15 of them found so far, and most of them are located in Cornwall.
06:24According to the estimates, those tunnels were built about 2,400 years ago, and they
06:29are still in pristine condition, which is truly fascinating.
06:34I mean, back in the day, people had no cool machinery whatsoever, yet their structures
06:40still last.
06:42And if you dare to buy an apartment today, well, chances are you won't be too happy
06:46about the quality.
06:50Going back to our fugus, there's nothing extraordinary about their supposed purpose.
06:54They could be used for spiritual purposes, as a place to hide, or a food storage.
07:01The latest application though is a bit weird.
07:04I guess it's not a secret for anyone that England is famous for its excessive humidity,
07:09and if you want to store your food properly, you gotta avoid the humidity at all costs.
07:14Otherwise, say welcome to mold and fungi!
07:18But ancient people weren't dull-witted at all, or they wouldn't have survived, and you
07:22and I wouldn't be around now.
07:25So they might have adapted those fugus to store just some products, those that already
07:30had natural molds in them, assisting in the preservation of perishable food, like milk,
07:35butter, and cheese.
07:37But hey, those are just speculations.
07:40The true reason why they were built remains unknown.
07:45What makes fugus unique is that they are intentionally built tunnels, not just excavated mines like
07:50those in Wales.
07:52They were crafted by digging deep trenches, lining them with stone slabs, covering them
07:57with capstones, and then filling over them, all of which took significant time and effort.
08:03Still, no matter how hard those were to construct, cities around the globe are often built over
08:10intricate tunnel systems, each unique to its location.
08:14For instance, Paris is famous for its extensive underground quarries, which were abandoned
08:20years ago, but still pose a risk of collapse in certain areas above.
08:26London boasts one of the largest tunnel networks in the world, including many that were specifically
08:31created for military purposes.
08:34In New York City, there are rumors of secret tunnels, while Los Angeles has old tunnels
08:40from the Prohibition era used for speakeasies.
08:44Many other cities also have their share of enigmatic tunnels, and surprisingly, Florida
08:49is no exception.
08:51It happened in the year 2011 in Ybor City.
08:54Near a former post office, flooding uncovered something weird, a section of an unknown structure.
09:01Back then, people didn't pay much attention to that, so it took another seven years to
09:05discover something truly fascinating.
09:09This historic neighborhood was founded in the 1880s, but it remained unknown until 2018
09:15that it also has a hidden tunnel network.
09:18We only learned of it because of renovation work.
09:21The exact purpose, of course, is unknown, but most scientists are pretty sure that they
09:27serve to connect to early gaming spots and the Port of Tampa.
09:32Figuring out how extensive the tunnel network is, is tricky.
09:36In 2018, a historic home in Seminole Heights revealed locked doors leading to tunnels from
09:42the 1920s.
09:44One local even said he traveled through a tunnel for 20 minutes.
09:48Rumors suggest some tunnels connect to the Hillsboro River and Ybor City.
09:54Research is ongoing, but no new info has emerged yet.
10:01That's it for today!
10:02If you pacified your curiosity, then give the video a like and share it with your friends!
10:07Or if you want more, just click on these videos and stay on the Bright Side!
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