In nature, it is always the highest mountain peaks, the most lush jungles or the most idyllic landscapes that attract our attention. In short, everything that is above ground.
However, underground we can also find magnificent and fascinating structures that you surely do not know.
Here are some of the most impressive “holes” on earth:
1- Superconducting Super Collider
Today, the particle accelerator The world’s largest, the superconducting Super Collier (SSC), is not as impressive as it could have been.
If it had been completed, the particle accelerator would count would have a circumference of 87 kilometers. Unfortunately, construction of the SSC went over budget and was abandoned.
The project was approved in 1987 with an estimated initial cost of $4.4 billionfunded primarily by the US Department of Energy. In 1993, the estimated total cost for the construction of the SSC increased to 11 billion. By the time it was abandoned, approximately €2 billion had already been spent digging 24 kilometers of tunnel.
To this day, the Superconducting Super Collider is regarded as the “the most expensive hole ever dug«.
2- Woodingdean Well
In 1858, in the town of Woodingdean, England, plans were drawn up to build a building for troubled youth. In order to obtain a water source close to the building, the construction of a well began in one of the courtyards of the land. All of their excavation was done manually by pulling buckets of earth up to the surface.
The initial plan was for a brick-lined pit of 122 meters. After two years of excavation, the well had reached 134 meters deep (slightly below sea level), and no water had yet been found.
At this point, several horizontal galleries were excavated, also without success. The men in charge of the project refused to admit defeat and ordered the excavation of a new vertical axis at the end of one of the horizontal ones.
This well was dug for another 2 years. The only light came from the candles, and the conditions were such that many men worked naked. Finally, after 4 long years of digging, on March 16, 1862, the well found water at 392 meters deepthus becoming the deepest hand-dug well in the world.
3- The Zacatón
El Zacaton, in Tamaulipas, Mexico, holds the title of the deepest chasm filled with water in the world, with a total depth of 339 meters.
The chasm is 140 meters in diameter where some “floating gardens”, known in Mexico as chinampaswhose main vegetation is the grass, grass, hence its name. These grass chinampas move along the surface dragged by the wind, which gives it a strange and original appearance.
This is a dangerous place for scuba diving, as it is full of underground caves so light does not reach it, leaving the diver in complete darkness. The water is sulphurous, thermal and not at all crystalline, which doesn’t help either. In 1994, the world’s best cave diver, Sheck Exley, died there attempting to break the 305 meter dive recordand in the same year Jim Bowden, “disciple” of Exley, reached 282 meters in the Zacatón.
4- Vrtoglavic Cave

Vrtoglavica cave is located near the Italian border in the Julian Alps of Slovenia. Its entrance is located at 1,900 meters above sea level on the slope of Mount Kanin.
Vrtoglavica means “vertigo cave» in Slovenian, and for good reason. A narrow, ice-covered, nearly vertical passage leads down the mountain. Eventually, the passage widens considerably to become a very deep well.
The Vrtoglavica cave is not characterized by being the largest, longest or deepest cave, but rather by containing the longest uninterrupted vertical drop in the world. It is possible for an object (or spelunker) to fall freely 603 meters before hitting bottom.
This pit also contains one of the longest underground waterfalls in the worldwhich extends for about 420 meters long.
5- Eiksund Tunnel

The Eiksund Tunnel in Norway runs underground through the Vartdalsfjord and connect the hareidlandet island with the mainland. It opened in 2008 as part of the Eiksundsambandet Project, which included other tunnels and a bridge intended to provide a permanent route between Hareidlandet and the rest of the country.
the eiksund it is the deepest tunnel in the worldreaching the 287 meters at its deepest point, making it the deepest place underwater where driving is possible.
6-Y-40 The Deep Joy

Do you remember trying to touch the bottom of the deep end of a swimming pool as a child? Imagine a pool approximately 10 times deeper, and you have the Y-40 Deep Joy Pool, the deepest pool in the world.
Located in Montegrotto Terme, Italy, the Y-40 features a vertical axis that descends to the 42 meters deep And contains 4.3 million liters of water.
The pool water comes from local hot springs and is kept at around 33ºC, allowing divers to swim without wearing a wetsuit.
7- Great Pagosa Aquifer

The Pagosa, Colorado Resort and Spa features several geothermal pools. For years, travelers have flocked to the pools for the healing effects of their waters.
These pools are fed by the Great Pagosa Aquifer, known locally as the “mother spring«. This natural hot spring is too hot for anyone to bathe in, reaching an average of 55ºC on the surface.
The mother spring averages 8 meters deep, but towards the center, geothermal waters rise from a much deeper hole. This hole descends to the 305 metersthus converting it to the deepest geothermal hot spring in the world.
It should be noted that this is the official measure, but not the true one, as it is still unknown. When measured, the survey line was exhausted at 305 meters without having reached the bottom.
8- Cave “dragon’s breath”
Located in the Kalahari desert, Namibia, the “dragon’s breath” cave gets its name from the moist air that you feel from your entrance. In 1986, it was discovered that this humid air was due to a large underground lake which was about 60 meters underground.
With an area that covers approximately 2 hectares, the lake in this cave is the largest underground lake in the world that is not located under a glacier. Its maximum depth is still unknown. For now the deepest point measured by man reached 91 meters.
9- TauTona Mine
TauTona (“big lion” in Setswana) is a South African gold mine that has been in operation since 1962. An expansion project was completed in 2008, achieving the 3.9 kilometers deepthus turning TauTona into the deepest mine in the world. An elevator ride from the surface to the bottom requires about an hour.
This impressive hole houses approximately 800 kilometers of tunnels in which 5,600 miners work in more than dangerous conditions. The air temperature can reach 55ºC, while the rock can reach 60ºC.