Krubera Cave: The Most Dangerous Cave on Earth

This post may contain affiliate links. By purchasing products through these links, I may earn a small commission at no additional cost to you. If you would like to learn more, please read this Disclaimer for details.

Beware: You should never explore wild caves alone or without proper gear. Consider getting in touch with a Grotto of the National Speleological Society at or a qualified cave club. These groups are skilled and will train you. Without sufficient knowledge, preparation, and equipment, cave exploring can lead to serious injury or death.

If you’ve read our article on Veryovkina Cave, you have already heard of Krubera Cave. For quite some time, Krubera Cave held the title of the World’s Deepest Known Cave. As of 2017, though, Veryovkina overtook Krubera and still holds the title today.

But the Krubera Cave fans needn’t be too upset – Krubera holds another title still: The World’s Most Dangerous Cave.

This natural wonder is famed among cavers due to its complex challenges and subterranean depth. It formed over hundreds of thousands of years by running water flowing through it. The limestone walls have eroded over time, creating a labyrinthine cave system with several chambers and passageways. Along with its sheer size and potential for exploration, this place is also home to many rare animals.

While visiting the cave, you’ll experience a magnificent underground world worthy of standing tall as one of the world’s greatest wonders. This article discusses its depth, history, and why it remains wholly unexplored today.

Where is Krubera Cave Located?

Krubera Cave is located in Abkhazia, a region currently occupied by Russia. It is considered the second-deepest known cave on Earth, with only its counterpart Veryovkina Cave exceeding it in depth.

Discovered in 1960, it earned its name as a tribute to a famous Russian geographer, professor, and founder of Russian karstology, Alexander Kruber. Kruber explored Western Caucasia early last century.

Today, Krubera Cave is known as a sub-vertical cave, accessible only using special equipment. Stalactites and stalagmites are found here, along with streams and small lakes. The River Repua gets its water from the Krubera Abyss.

Krubera Cave Measurements

A map shows the extensive winding descent in Krubera Cave.

Before you even get inside, it’s easy to assume you’re looking down at a bottomless pit. Krubera Cave has been forming for nearly five million years, and measures over 7200 feet (2197 m) from top to bottom. To give you an idea of its depth, it’s about six times deeper than the Eiffel Tower.

Krubera is also special in that it starts high in the mountains, with a narrow entrance at an altitude of 7400 feet (2,256 m).

While exploring the cave’s deepest reaches, explorers had to carve away rock at several points to allow safe passage.

One thing that makes Krubera Cave so unique is the many tunnels within it. Most of them are flooded, which makes them “sumps” (areas with low air pressure). The deepest sump ever explored is up to 52 meters deep.

But while it’s small in some places, in others, it’s as large as a subway tunnel. This cave-and-tunnel system within Krubera Cave makes it even more challenging to reach the bottom.

For over 20 years, explorers have studied the intricate passageways and pits of Krubera Cave. But now that a reliable map has finally been drawn up, some believe there are still unexplored areas within its depths.

The Mount Everest of Caves

Krubera Cave has earned the nickname “Everest” due to its extensive cave system. Teams attempt to reach the bottom each year, similar to the recent excitement associated with reaching the top of Mount Everest.

Several climbers descend a steep vertical shaft in Krubera Cave.

But just as Mount Everest comes with serious demands, with high altitude and lack of oxygen and atmosphere, Krubera Cave features its own.

The pressure mounts (no pun intended), as you reach depths several thousand feet below the surface. Not everyone can go.

Just like with scaling Everest, this descent requires excellent planning and resources, including tents and breathing equipment.

Mount Everest was established as the highest peak in the mid 1800s. Krubera is still quite young in that regard, having been known for about 60 years. In addition, it was only considered the deepest cave since 2001, until Veryovkina Cave supplanted it in 2017.

Some of the channels in Krubera Cave are basically impossible for human beings to maneuver through, and it’s fair to call it a labyrinth. With such tight corridors and being such a remote location with no chance of finding help, it’s clear how it can be easy to end up trapped and have no chance of rescue.

But it gets worse. There’s water in several tunnels, as well as a sump at the very bottom. The passages are extremely steep, and deeper regions show conduit patterns characteristic of high-gradient floods.

The complex structure of the massif, due in large part to faulting and its effect on water flow systems, has dramatically influenced the development of caves.

It’s safe to say there’s quite a lot unknown still about this cave. With the race to the top (or bottom) between Krubera and Veryovkina, it may reclaim the title of the deepest cave with future discoveries.

Speleological History Of Krubera Cave

It was not until the 1960s that explorers could enter the cave. Previously, its existence was known but had yet to be explored.

Soviet speleologists were the first to study Krubera Cave. They reported that they believed an underground system existed below a profound depth. Alexander Kruber wrote papers about the caves that helped to establish knowledge about their geology.

Crow’s Cave (Vronja) is another name for the site, reflecting its popularity with local crows.

Large-scale expeditions into the caverns occurred again in the 1980s when a group of Ukrainian speleologists conducted their first expedition. They could push down narrow connecting chambers and through tight choke points, reaching a depth of 900 feet (274 meters).

The downfall of the Soviet Union and its instability caused researchers to abandon exploration of the cave for two decades.

In 2001 American explorers rekindled interest in the cave, and on a series of Krubera expeditions, they discovered new pits, meanders, and passages. Underground divers explored wet areas of the cave system.

Inside Krubera Cave

Krubera Cave is so deep that it gives excellent insight into what life would be like for humans if we lived underground. The stunning landscape will leave you speechless.

Explorers must gradually descend with ropes, and its sump, an underwater reservoir at the bottom of the cave, features a deep pool of water.

Experts have also found a frozen waterfall in the cave that accounts for more water drainage leading to more chambers filled with icy H2O. This frozen fall is one of its unique features, but there are many others.

The narrow underground channels in the cave are nearly impossible for any human to navigate without some indication of where they’re going, making it a literal labyrinth.

This network of underground channels and tunnels is water-filled, so it’s difficult to know where each route will lead or what twists and turns lie ahead. In 2005, National Geographic assembled its global team to attempt mapping out at least some of this cave system.

The explorers returned with incredible photos, recordings, and a detailed map of all the explored areas. But even after that trip, no one has been able to travel through every passageway in this remarkable cavern.

Biology In The Cave

The Krubera-Voronja cave system is home to more than 12 species of arthropods belonging to several groups: pseudoscorpions, spiders, Opiliones (pillbugs), crustaceans such as Isopoda and Copepoda; springtails (Collembola); beetles and dipterans.

Four springtails (wingless insects) discovered in 2010 live only deep within the cave: Anurida stereoodorata, Deuteraphorura kruberaensis, Schaefferia profundissima, and Plutomurus ortobalaganensis.

The deepest terrestrial animal ever found on Earth is the beetle Catops cavicis. It lives 1,980 meters (6,500 ft) below the cave entrance of Krubera-Voronja and several caves around Ortobalagan Valley.

The Kruberia abchasica, a crustacean that lives at the bottom of the Krubera Cave, was caught by Gennady Samokhin during his dive in August 2013.

Want to know more about cave animals? Read about some other interesting species here.

Why Krubera Cave Remains a Mystery

It’s easy to see why Krubera Cave’s bottom is tough to get to. But the cave itself is located in an area that isn’t easily accessible either. This region has been under-explored, and much is unknown. This leads to curiosity about the cave’s mysteries and its immediate surroundings.

It took two weeks for the teams to carefully make their way down to catch sight of this beautiful cave.

But the demand is certainly there. The discovery of new caves such as this one helps scientists understand more about them, how they were formed, what ecological niches exist within their walls, etc. There are still many caves that remain unexplored on Earth’s surface.

Krubera is likely to remain a mystery until scientists can find a way to explore its underground tunnels without endangering the divers who chart them.

Until then, we’ll have to settle for the unknown depths of a cave shrouded in mystery, potentially more profound and likely more dangerous than any other on Earth.

With a freezing underground waterfall, entire areas filled with water, and narrow tunnels, we think the ‘Most Dangerous Cave’ title is fitting. It’s too easy to get trapped or lost here, and without a professional team there would be no chance of anyone knowing in time.


So, the bottom line is this: Krubera Cave is one of the most outstanding geographical features ever discovered. It’s also one of the most significant caves in the world and deserves a larger body of knowledge about it.

The good news is that with teams making efforts to explore more each year, it should receive broader recognition. However, even Everest took over 100 years to become fully appreciated, and we will have to see if Krubera Cave becomes somewhat more commercialized in the coming years as well.

If you’re looking for some more dangerous caves, check out our article on the world’s most dangerous caves next.

This book also shares some interesting insight on the descend into Krubera Cave.  It’s called Blind Descent: The Quest to Discover the Deepest Place on Earth. Bill Stone, from America, and legendary Ukrainian explorer Alexander Klimchouk team up to tackle one of the most difficult challenges any human beings faced.

Must Read!
Blind Descent: The Quest to Discover the Deepest Place on Earth

When reality is more suspenseful than fiction, you know you're in for a hell of a story.

Contending with "thousand-foot drops, deadly flooded tunnels, raging whitewater rivers, monstrous waterfalls, and mile-long belly crawls," a few supercavers sought out to blaze the trail that was unexplored.

This incredible book tells of "psychological horrors produced by weeks plunged into absolute, perpetual darkness, beyond all hope of rescue."

If you've got a thirst for adventure, you will surely enjoy reading about one of the toughest in caving history.

Leave a comment