The most large caves the planets amaze with their grandeur, which can fascinate anyone. It's scary to look into the trap of a huge cave. It seems impossible to get back out of this place. This mysterious one separate world silence and silence can suck any unwary tourist into its open spaces.
Expeditions to study the most complex caves began in the 18th century. The then famous scientist I. Nagel led the largest expedition to the caves of Moravia. During the expedition, the group reached a depth of 138 m.
M. Lomonosov contributed a large amount of knowledge about underground depths. Explanation of the chemical nature of caves - Lomonosov's theory. The movement of air at the depths of caves and the formation of stalactites and stalagmites, as well as the formation of ice in caves - this knowledge is the merit of our scientist.
Absolutely all caves are different from each other, but they can easily be included in the list of the most unusual places on Earth. The presence of wells, lakes, grottoes, waterfalls and glaciers are the elements of caves that create the overall picture and make certain differences.
For centuries, water erodes rocks and creates huge labyrinths of mysterious and powerful caves. What are the sizes of the largest caves on Earth?
We present to your attention 7 of the largest caves on Earth.
Kruber Cave.
Krubera Cave is also called Crow Cave. It is one of the deepest caves on the planet. Voronya is the only cave that has a depth of more than 2 km. It is located in Georgia. The entrance to its expanses is located at an altitude of 2249 m. The vertical cave has many wells, which are connected by a large number of climbs. At a depth of about 200 meters, the cave divides into 2 branches. The main branch has a depth of 2197 m. Nekuibyshevskaya - 1698 m. 
Krubera Cave was discovered in 1960 by an expedition of the Research Institute named after. Bagrationi. The Crow Cave has seen a huge number of different expeditions and scientific research.
Jeita Caves.
The Lebanese Great Caves are some of the most magical caves on Earth. The upper cave was discovered in 1836, the lower one much later - in 1958. The length of the cave is 2250 m. 
Jeita is very popular among tourists, who have the opportunity to visit only part of the cave, 700 m deep, the rest of the path is blocked. The upper cave has 3 halls and special underground reservoirs. Stalagmites and stalactites also decorate the view of the Lebanon Cave.
Mammoth cave.
The Mammoth karst cave system is located in Kentucky (United States).
A national park was built there, and the cave is its attraction and pride. Mammoth Cave is considered the longest cave in the world (588 km). Mammoth Cave has 226 underground passages, as well as more than 20 halls and 25 deep shafts. 
By the way, the name “Mamontova” is not associated with any surname or with mammoths. "Mammoth" means "huge".
It is known that Mammoth Cave was formed more than 10 million years ago. The Indians knew about its existence. This fact was confirmed by scientists after Indian cemeteries with mummies were discovered in the cave.
Caves of Crystals.
Crystal Cave is the most unusual and amazing cave in the whole world. It is located in Mexico and is unique because... it is filled with giant gypsum crystals. The largest crystal was discovered at the beginning of the 20th century. It is 11 meters long and weighs 54 tons. The temperature inside the cave exceeds +50°C with 100% humidity. 
The cave was discovered in 1910 by Mexican miners. The Ice Palace is the most famous hall of the Crystal Caves complex. It was discovered during drilling work in 2009. Oddly enough, with its depth of 150 m, the hall is not filled with water.
Dragon Caves.
The Dragon Caves are of amazing beauty and are the main mystery of Mallorca. Exploration of these caves began in 1886. 
The caves are 1250 m long, equipped with special lighting equipment and a huge auditorium, which was built to host various shows and concerts. Musical performances take place on boats on Lake Martel.
Son Doong Cave.
The largest cave in the world is located in Vietnam. They learned about it in 1991, and in 2009 a group of British scientists began an in-depth study of Shondong. The cave with the highest and widest passages has a total volume of 38 million m³. 
Shondong has its own jungle (the height of the trees reaches 3 meters) and a river flows with enough fast current.
Optimistic cave.
The cave is located on the territory of Ukraine and reaches a length of more than 200 km. The cave, discovered in 1966, has not been fully studied. In the cave, in addition to stalactites, there are formations reminiscent of the crystals of the Crystal Cave in Mexico. However, the Optimistic Cave crystals are much smaller. 
The cave received the name “Optimistic” because, contrary to the predictions of other scientists, Lvov speleologists considered the cave to be one of the largest in the USSR. As a result, their assumptions were confirmed.
Son Doong is a cave in Central Vietnam that currently holds the title of the largest cave in the world. It is located in the heart of Phong Nha-Ke Bang National Park in Quang Binh Province, not far from the Vietnam-Laos border. Its dimensions reach record levels - the height is 200 meters, the width is 150 meters, and the length is more than 5 kilometers. The total volume of the unique formation is 38.5 million m³.
The entrance to the cave, located deep in the jungle, was first found by a local resident named Ho Hanh in 1991, but the roaring water flow coming from there and the steep descent prevented him from exploring it from the inside. Only in 2009, a group of British scientists led by Howard Limbert managed to discover and successfully study Son Doong in Vietnam, after which they announced the official opening of the cave and confirmed that its dimensions allow it to be awarded the status of the largest on the planet.
“Hang Sơn Đoòng” is translated from Vietnamese as “mountain river cave”. It does have a fast-flowing underground river that floods parts of Shondong during the rainy season. In addition, it has its own jungle, climate and even real clouds, which are formed due to the large temperature difference. The giant underground cavity's two huge windows allow light to flood into many parts of it, creating a lush jungle with 3-meter-tall trees inside.
Shondong is famous not only for its impressive size, but also best examples cave formations all over the planet. Here you can find interesting ancient fossils, stalactites and some of the tallest stalagmites in the world, up to 70 meters high. A particularly impressive formation is the Dog's Hand and a place called the Cactus Garden. Also in the cave there are examples of giant cave pearls that fill the limestone layers.
The flora and fauna of Shondong is a treasure trove for any scientist. Many rare plant species grow in the cave area, and recently a number of new animal species have even been discovered. Monkeys, hornbills and flying foxes all live in this unusual underground jungle.
The unique cave was formed as a result of a long process of washing away limestone by water flow approximately 2-5 million years ago.
At the beginning of August 2013, the first tourist group went on an excursion to Shondong. To get inside the attraction you need using a ropego underground to a depth of 80 meters. Tourists set up a tent camp there, spending time in the labyrinths underground cave or sitting comfortably by the fire. The cost of such entertainment is $3,000. From September to March, access to the cave is closed due to the rainy season, during which many areas are flooded. The 2015 tour schedule will be posted on the tour website later this year.
The world's largest cave, called Sơn Đoòng, has attracted a lot of attention from many film companies such as BBC, National Geographic, as well as famous Japanese and Brazilian teams. In 2011, she appeared on the pages of the popular National Geographic magazine.
The underground world has long attracted the attention of people. In ancient times it was inhabited by gods. Nowadays, we have begun to explore the deep bowels of the planet, which are unique labyrinths of underground galleries, halls and mines.
Today the caves are of interest to both speleologists and ordinary tourists. Scientists use them to study the history of the development of the Earth, explore various mineral formations, and discover new biological species. Tourists flock to caves for adventure. The underground galleries decorated with stalactites and stalagmites captivate the imagination, excite the imagination and fill even the most callous hearts with horror and romance.
On any continent, in any country, you can find underground passages, most often formed by water, which, century after century, erodes the soil and rocks. Most modern caves are classified as “dry”, but there are some among them where underground rivers still flow.
Almost all caves are actively being studied, but the longer the underground formation, the more difficult and longer this process takes.
Each of the caves has its own unique structure and system of natural entrances: somewhere there may be several of them, somewhere only one, and somewhere more than a hundred. Artificial passages are made to caves with limited access.
Many famous caves have underground camps for scientists and specially designed tourist areas for general visitors. National parks are often formed around caves, allowing the unique natural heritage to be preserved intact.
Planet Earth caves - VIDEO
Caves of the world - PHOTO
1. Mammoth Cave
The longest cave in the world was discovered in 1797 in the Appalachian Mountains, located in the US state of Kentucky. Its underground passages and halls go six hundred and fifty-one kilometers deep into the earth. The cave was formed about ten million years ago as a result of the dissolution of rocks by water. It got its name due to its size: translated from English “mammoth” - “huge”. The cave has a special microclimate. It contains amazing eyeless creatures that look like fish.
2. Sak-Actun
The Mexican cave of Sac Actun is the longest in the country and the second longest in the world. It was opened in 1987 in the north of Yucatan, near the city of Tulum. Of the three hundred and seventeen kilometers of underground passages, only six are not flooded. The “White Cave” (this is how its name is translated from the Mayan language) is of meteorite origin: scientists believe that it was formed about sixty-five million years ago as a result of the fall of a celestial body. The river of the same name flowing through the cave has perfectly clean and transparent water.
The American Jewel Cave, located in South Dakota, near the town of Custer, boasts a length of two hundred and fifty-seven kilometers. The height difference between its underground galleries is one hundred thirty-five meters, that is, four floors. The cave was discovered in 1900. Jewel has one natural (in the northwest) and one artificial (in the center) entrance. All of its galleries, except the top one, are covered with a thick layer of calcite - a transparent or white calcareous mineral. Interesting feature cave is the presence of strong winds, up to fifteen meters per second.
4. Ox-Bel-Ha
“Three Ways of Water” is only a kilometer shorter than Jewel. The cave located not far from Sak-Actun has not yet been fully explored, but more than one hundred and forty natural entrances have already been discovered in it. Aux-Bel-Ha was formed eighteen thousand years ago by the waters of the world's oceans, which exceeded their level due to climate change and eroded nearby limestone rocks. The Mexican cave reaches a depth of thirty-seven meters and has about eighty branches, flooded by the waters of the Caribbean Sea.
5. Optimistic
Located in the Ternopil region, near the village of Korolevka, the Ukrainian Optimistic Cave reaches a length of two hundred thirty-six kilometers, but has a shallow depth - no more than fifteen to twenty meters. The fifth longest among all the caves in the world, it is the first among gypsum formations. Optimistic Cave was opened in 1966. Currently, the underground passages of the village of Korolevka are being actively studied: for scientists from different countries In the world there are fifteen underground camps in the cave.
American Wind Cave is Jewel's neighbor. It is smaller in size by forty-five kilometers and is just as deep. Wind has been known to people since 1881. Since 1903, it, together with the adjacent territory, received the status of a National Park. The cave was formed by thermal waters. Now they find on its walls a large number of minerals. From a geographical point of view, Wind is a labyrinth filled with a dense, branched network of underground galleries. The cave is equipped for excursions. About five hundred thousand tourists visit it annually.
7. Lechugia
The American Lechuguia Cave stretches underground for two hundred and twenty kilometers and goes approximately five hundred meters deep. It was opened in 1914, but until 1986 no one was interested in it, since everyone saw it as a “Dreary Hole” (the first name of Lechuguia) and nothing more. Today, the unique rock formation is part of Carlsbad Caverns National Park. Speleologists consider Lechuguia the most beautiful cave in the world, thanks to the finest lace of gypsum crystals covering its walls.
The longest European cave is located in the Swiss Alps. It was opened in 1875. With a length of two hundred kilometers, its depth reaches a thousand meters with an vibration amplitude of more than eight hundred meters. There are two entrances to Hölloch: the first is located in the valley of the Muota River, the second is at an altitude of more than a thousand meters. The cave consists of a complex multi-story system halls and galleries decorated with numerous stalactites and stalagmites. In summer, floods are observed on its watercourses. The lower part of Hölloch is open to tourists.
9. Gua-Air-Jernich
The longest Asian cave is located in the north of the Malaysian island of Kalimantan. Opened relatively recently, in 1978, it has a length of one hundred and ninety-seven kilometers. The amplitude of Gua-Eir-Jernich is three hundred and fifty-five meters. The cave has five levels of galleries and many entrances. The main entrance is in the river. You can get to it by boat. The lower level of Gua Eir Jernich is filled with water. The cave is part of Gunung Mulu National Park, which includes other karst formations and rainforests.
10. Fisher Ridge
Located in the western Appalachians, the Fisher Ridge karst cave reaches a length of one hundred and ninety-four kilometers. Underground labyrinths, going one hundred meters deep into the earth, were discovered in Kentucky in 1914, although they have been known to the indigenous people of the United States for the past thousand years. Fisher Ridge is located in close proximity to Mammoth Cave. It has three entrances leading to a multi-level complex of galleries and shafts. The Green River flows through the cave. The walls of Fisher Ridge contain rock art.
No human structure can compare with the greatest caves in the world in beauty and grandeur. We offer you a selection of twenty of the most stunning caves and grottoes from all over our planet.
Caves are one of the most amazing creations of nature. Among the many dirty and damp “sheds” there are real palaces and temples, as if created as a mockery of the architectural tricks of people. No human structure can compare with the greatest caves in the world in beauty and grandeur. We offer you a selection of twenty of the most stunning caves and grottoes from all over our planet.
1. Cave of Crystals (Cueva de los Cristales), Mexico
The cave of crystals was discovered in 2000 by the Sanchez brothers, miners who were digging a new tunnel in the mine complex. It is located 300 meters below the city of Naica, Chihuahua, Mexico. The cave is unique for the presence of giant selenite crystals. The largest crystal found is 11 m long and 4 m wide, weighing 55 tons. These are some of the largest known crystals. The cave is very hot, temperatures reach 58 °C with a humidity of 90-100%. These factors make it very difficult for people to explore the cave, making it necessary to use special equipment. Even with equipment, the stay in the cave usually does not exceed 20 minutes.
2. Waitomo Glowworm Cave, New Zealand
Waitomo Caves are truly a masterpiece of nature, on which she has worked for many millions of years. For many centuries, the ocean ruled here, creating bizarre limestone growths and mysterious intricacies of passages. And then the water receded, forming a system of about 150 caves. The most famous of them is Glowworm Cave. It is inhabited by amazing creatures - Arachnocampa Luminosa. These are fireflies that can only be found in New Zealand. Their green-blue glow makes the cave roof look like a starry sky on a frosty night.
3. Blue Grotto (Grotto Azzurra), Italy
This is a beautiful cave, accessible only from the sea. The name “Blue Grotto” comes from the bright blue color of its waters. The entrance to the cave is very small and lets in a small amount of light, which gives the water its bright color.
4. Vatnajokull Glacier Cave, Iceland
Sunlight, scattering across the surface of the Svínafellsjökull glacier, paints amazing pictures on the arches of the ice cave, creating the illusion of being on deep sea. The depth of the underground passage does not exceed 50 meters, and the width of the cave is only 10 meters. IN winter months A cracking sound is heard inside, caused by the movement of the glacier.
Such pure azure and blue shades are the result of the absence of air bubbles in the ice. You can see colored ice under certain conditions weather conditions; one of them is the absence or minimal amount of snow on the surface. The rich sky blue ice is best seen in January and February; It is during this period that shades of azure, framed by snow cover, look fantastic.
You can get into the cave only in the winter months: narrow ice passages are accessible to tourists only with the onset of frost. At other times, being here can be dangerous; melting ice vaults often collapse under the snow mass.
5. Phraya Nakhon, Thailand
It's not actually a cave, but a huge valley that is 65 meters deep and 50 meters wide, with overhanging walls covered with plants and stalactites. IN certain hours daylight enters the interior, illuminating the small temple
6. Marble Caves of Patagonia, Chile
Despite their name, they are made of ordinary limestone, but there is an opinion that in the depths of the caves there are pure deposits of marble. The walls of the Chilean landmark are a surprisingly beautiful bright blue color, and the blue water of the lake doubles the impression of what you see. It is also worth mentioning that the caves consist of many labyrinths and tunnels, the creation of which was worked hard by the coastal waves.
7. Glacier caves in the area of Mutnovsky volcano, Russia
A small and very beautiful snow cave on the slope of the Mutnovsky volcano.
8. Dongzhong Cave, China
Dongzhong Cave (whose name simply translates as “cave”) is located in the village of Mao in the Chinese province of Guizhou. Since 1984, the cave has been equipped as a primary school.
9. Fingal's Cave, Scotland
A famous sea cave, washed out of the rock by sea water, on the island of Staffa, part of the Inner Hebrides group of islands. The walls are composed of vertical hexagonal basalt columns 69 meters deep and 20 meters high. For three centuries it has been a place of artistic pilgrimage and has inspired the work of many famous artists, musicians and writers.
10. Reed Flute Cave, China
Reed Flute Cave (Ludi Yan) is an amazing creation of nature located in Guilin (China). Around the cave grows a special type of reed, from which in the old days the best flutes in all of China were made, it was this fact that served as the basis for this beautiful name. The Ludi Yan Cave, like the Waitomo Cave, has lighting, only not natural, but “artificial” - artificial. With its help, the Chinese successfully emphasize the beauty of nature’s impeccable creation. Multi-colored lights playfully color stalactites and other bizarre rock formations, making the cave even brighter and more fabulous.
11. Fantastic Pit at Ellison’s Cave, Georgia, USA
If you are an extreme sports enthusiast and also an amateur caver, then Ellison Cave is ideal for you, namely its bizarre 179-meter deep shaft.
12. Kyaut Sae Cave in Myanmar
Few people know about this cave, but nevertheless it is stunning both for its size and for the fact that it houses a Buddhist temple.
13. Son Doong Cave, Vietnam
The largest cave in the world. It is located in Central Vietnam, in Quang Binh Province, in national park Phong Nha Ke Bang, 500 kilometers south of Hanoi and 40 km from the provincial center - Dong Hoi. This cave has been known to local residents since 1991; in April 2009, it was discovered by a group of British speleologists. The cave has an underground river that floods some parts of the cave during the rainy season.
14. Ice Cave Eisriesenwelt, Austria
The Eisriesenwelt caves are the most big system ice caves on our planet, available for viewing. Translated, Eisriesenvelt means “giant ice world.” The caves are located in the Alps in Austria at an altitude of 1641 meters and consist of 30 thousand cubic meters. meters of ice. These caves were formed by the waters of the Salzach River, which over thousands of years eroded the limestone rocks. Currently, the river bed is located below the entrance to the caves.
The Eisriesenwelt caves were discovered by accident back in 1849. For a long time Only hunters and poachers knew about them. The official opening date of the Eisriesenwelt caves is considered to be 1879, when the Austrian naturalist from Salzburg, Anton von Posselt-Czorich, first penetrated 200 meters deep into the caves. A year later, he published a detailed report about his discovery in a mountaineering magazine, but this information did not arouse sufficient interest.
15. Ordinskaya Cave, Russia
Orda Cave is the longest underwater gypsum cave in Russia and one of the longest in the world. This place is a real paradise for divers. The cave begins with the Crystal Grotto. In the northwestern corner of this grotto there is Lake Ledyanoe. The passage on the left will lead to the next grotto - the Ice Palace. Here is Lake Main, and a little further away is Lake Teploe. Through these lakes, divers enter the mysterious underwater part of the cave. The water here is extremely clean, transparent, bluish in color and very cold (+ 4 degrees)
16. Carlsbad Caverns, USA
Under the arches of the Guadalupe Mountains in New Mexico hide endless labyrinths of halls, tunnels and corridors, the main inhabitants of which are bats. The charm of the Carlsbad Caverns becomes more charming and mysterious with the advent of dusk. The park and caves got their name in honor of the nearby city of Carlsbad.
17. Barton Creek Cave, Belize
This cave not only has extraordinary natural beauty, but is also a living witness to the household items of the ancient Mayans, who inhabited this territory more than 2000 years ago. In it you can see many grandiose stalactites and stalagmites, ancient jugs and religious bowls of the May Indians, traces of religious human sacrifices
18. Jeita Grotto Caves, Lebanon
a complex of two caves in Lebanon 20 kilometers north of Beirut. The upper cave was discovered in 1836 by William Thomson, and the lower cave was discovered in 1958 by Lebanese speleologists. The length of the Upper Cave is 2200 meters, but only a part of it, which is 750 meters long, is open to tourists. The Upper Cave has three halls, each of which reaches a height of 100 meters or more. There are unique underground reservoirs, very beautiful crevices, various stalagmites and stalactites. The length of the Lower Cave is much larger than the Upper Cave and is equal to 6900 meters
19. Kango Caves, South Africa
Cango Caves, unofficially called a wonder of the world. The caves are famous for their “Organ Hall” - stalactites descending along the walls here form something reminiscent of a large organ, which, combined with music and lighting effects, makes an indelible impression on visitors
20. Aven Armand Cave, France
A special funicular takes visitors 50 meters deep through a tunnel that is 200 meters long. There suddenly turns out to be a huge hall that could easily fit Notre Dame Cathedral in Paris