00:00In the ice caves of the Mount Rainier, in the United States,
00:03bright shades of blue and white shape spectacular sculptures
00:08that sparkle like jewels.
00:10But it is necessary to keep your distance,
00:12because these fragile formations are constantly at risk of collapsing.
00:16As temperatures rise, blocks and fragments of ice,
00:20sometimes as voluminous as a small car,
00:22detach from the ceiling of the caves and crash to the ground.
00:25Explorers must also deal with a danger of hypothermia
00:29caught between a glacial air and an even colder melt water
00:33flowing from the snowfield.
00:34As the melt intensifies over the hours,
00:37the caves become even more perilous in the afternoon.
00:40If you plunge into the strange expanse of water of Plura,
00:43in Norway,
00:44then swim underground for about 500 meters,
00:47you will come across a vast cave with vivid shades,
00:50where limestone and marble sculpt sinuous and steep passages.
00:54If you are an amateur diver,
00:56practicing this sport for fun,
00:58your exploration may stop there.
01:00However,
01:01this underground network is the deepest in northern Europe.
01:04The most experienced divers,
01:06with rigorous training,
01:07can continue the exploration in glacial waters and absolute darkness,
01:11where the course sinks quickly
01:13and becomes narrow and exhausting.
01:16In winter,
01:17the temperature drops to 2 ° C.
01:20Alas,
01:21the history of this cave is marked by dramas.
01:24In Texas,
01:25Jacobs Well
01:26looks like a peaceful 3.70-meter-diameter pool,
01:30inviting you to swim.
01:32However,
01:33under this deceptively serene surface,
01:36hides a formidable gulf,
01:38leading to a complex network of underwater caves.
01:41After a vertical descent of about 9 meters,
01:44the conduit tilts in depth
01:46through a succession of cavities
01:48invaded by sediments,
01:50separated by narrow passages,
01:52to reach an average depth of 36 meters,
01:55the equivalent of the height of a large wheel.
01:58Despite its seductive appearance,
02:00the well caused the death of 9 people
02:03between the 60s and 80s.
02:05However,
02:06some believe that the real balance could be higher.
02:09This is why these obscure and mysterious depths
02:12remain among the most dangerous diving sites in the United States.
02:16By plunging us deeper and deeper into the depths,
02:19we reach the Verjovkina Gorge in Georgia,
02:22known to be the deepest in the world.
02:25With its more than 2,200 meters of depth,
02:28it plunges into an unknown abyss
02:30where the risk of deadly cranes
02:32caused by underground and real sources.
02:35At its most accessible point,
02:37we discover a seizing turquoise lake,
02:40raised in a black limestone screen like the night.
02:43This place,
02:44as fascinating as it is disturbing,
02:46can quickly turn into a deadly trap.
02:49When a storm breaks out,
02:51the thunder crack resonates in the cave
02:54with a deafening intensity,
02:56while the water rises at an alarming speed.
02:59In these conditions,
03:00explorers have no second to lose.
03:02They must immediately find a way out.
03:05Caves and storms form a highly dangerous combination.
03:09The most striking example
03:11is the 2018 incident that captivated the whole world.
03:14Twelve young members of a junior football team,
03:17accompanied by their coach,
03:19went to explore a natural cavity
03:21in Chiang Rai province, Thailand.
03:23By bike,
03:24they climbed the woody hills
03:26to reach the Tam Luang cave.
03:28Careless,
03:29they plunged into the cave
03:31with their flashlight,
03:33convinced to stay there for only an hour.
03:35But they only came out of it 14 days later.
03:38Shortly after their entry,
03:40torrential rains poured down,
03:42submerging a part of the underground network,
03:44condemning their exit
03:46and imprisoning them in the depths.
03:48This is how the whole world
03:50has taken the measure of the danger
03:52represented by the Tam Luang cave.
03:54The Khitoum caves,
03:56located at the heart of the National Park
03:58of Mount Elgon, in Kenya,
04:00are among the most feared cavities in the world.
04:03Their walls are striped in size,
04:05which, at first glance,
04:07evokes the work of miners
04:09in search of precious stones or rare metals.
04:11However,
04:12it turned out that these singular marks
04:14were the work of elephants
04:16extracting the sodium salt contained in the rock.
04:18But if this particularity intrigues,
04:20it is not what makes these caves
04:22truly disturbing.
04:24They are, in fact, sadly famous
04:26for having served as home
04:28to some of the most deadly viruses
04:30in human history.
04:32As a precaution,
04:34it is better not to stay away.
04:36In Mexico,
04:38the Naica mine reveals a striking spectacle
04:40majestic above the visitors.
04:42This almost unreal landscape
04:44is not limited to a visual feat.
04:46It also bathes in a suffocating heat,
04:48temperatures
04:50can climb up to 54 degrees.
04:52In addition,
04:54the ambient humidity
04:56oscillates between 90 and 99%,
04:58making the atmosphere
05:00even more oppressive.
05:02Before imagining an excursion
05:04to this fascinating place,
05:06however, know that the cave
05:08can only be entered by scientists
05:10who have a special permission,
05:12provided they wear
05:14appropriate protective equipment.
05:16Cape present on New Zealand
05:18where the Cathedral Cave is located.
05:20A spectacular set of two limestone
05:22marine caves linked to each other
05:24and nestled in the beach of Waipati.
05:26With 200 meters of tunnel
05:28culminating at impressive heights
05:30of 30 meters,
05:32it is one of the most remarkable
05:34marine formations in the world.
05:36These caves have been carved
05:38over the millennia
05:40by the incessant hammering
05:42of the waves on the rock.
05:44Their name comes from their
05:46exceptional acoustics reminiscent
05:48of those of cathedrals.
05:50However, lovers of Gregorian songs
05:52will have to wait
05:54because access to these caves
05:56is only possible at low tide.
05:58For security reasons,
06:00visitors are only allowed
06:02to enter it when the weather conditions
06:04are favorable.
06:06It is better to avoid the Bracken Cave
06:08in Texas.
06:10Every summer, this dark cave
06:12welcomes the largest
06:14bat colony in the world.
06:16No less than 20 million bats
06:18from Mexico's Molossidae
06:20find refuge there between March and October.
06:22Those who dare to approach
06:24describe a fascinating spectacle.
06:26A real aerial ballet
06:28where millions of bats emerge
06:30in perfectly synchronized waves
06:32a sound that some compare
06:34to the soft hammering
06:36of a fine and regular rain.
06:38Now let's go to the equator
06:40where the mysterious Cueva de los Tallos
06:42is hidden.
06:44An enigma that intrigues
06:46explorers and researchers
06:48for decades.
06:50Nestled in the Andean jungle
06:52of the southeast of the country,
06:54this cave is only accessible
06:56by descending a vertical well
06:58of 70 meters,
07:00connected by narrow galleries.
07:02Some of these cavities
07:04are adorned with stalactites
07:06and stalagmites,
07:08adding to the disturbing atmosphere of the place.
07:10And if that is not enough
07:12to make the curious shudder,
07:14the cave would also house
07:16ancient artifacts and secrets
07:18buried in lost civilizations.
07:20According to some theories,
07:22it would contain a metallic library
07:24composed of engraved gold plates
07:26relating an unknown history of humanity.
07:28It is said that the tunnels,
07:30too regular to be natural,
07:32would have been shaped
07:34by an ancient civilization,
07:36even with the help
07:38of an extraterrestrial technology.
07:40These rumors have aroused
07:42the curiosity of many researchers
07:44to the point of attracting Neil Armstrong,
07:46yes, the astronaut,
07:48on an expedition aiming
07:50to unravel the mysteries.
07:52However, despite all these explorations,
07:54the Cueva de los Tallos
07:56Just like the Cueva de los Tallos,
07:58the last cave of our selection
08:00is not particularly dangerous,
08:02but it will not fail to give you chills.
08:04Just take a look at this wall
08:06of stone entirely covered
08:08with handprints.
08:10What seems straight out of a horror movie
08:12is actually the Cueva de las Manos,
08:14in Argentina.
08:16Its name means
08:18Hand Cave.
08:20And getting to these prehistoric paintings,
08:22about 13,000 years old,
08:24is a real challenge.
08:26The most timid travelers
08:28have to face a one-and-a-half-hour hike
08:30through a steep terrain
08:32to reach the site.
08:34But once inside,
08:36they are immediately caught
08:38by the artistic and symbolic
08:40power of these ancestral remains.
08:42It is estimated that nearly 800 handprints
08:44decorate the walls of the cave.
08:46Of various sizes,
08:48some are small,
08:50others long and thin,
08:52some are for women and children.
08:54Their authenticity makes no doubt,
08:56which only adds to the fascination
08:58they exercise.
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