Divers Explore The World's Deepest Underwater Cave


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Krzysztof Starnawski, left, and Bartlomiej Grynda, right, are reading images from a remotely-operated underwater robot, or ROV, that went to the record depth of 404 meters (1,325 feet). AP Photo/ Marcin Jamkowski

It’s easy to feel the days of grand explorations are all said and done. But this Czech-Polish team led by cave diver Krzysztof Starnawski are proving that our world is still ripe with discovery and mystery.

Last week, the explorers discovered more of the world’s deepest underwater cave, a flooded abyss called Hranicka Propast in eastern Czech Republic. The expedition was partly funded and first reported by National Geographic.


They managed to find it was at least 404 meters (1,325 feet) deep – and that’s a conservative guess. The endeavor involved Krzysztof Starnawski diving to 200 meters (656 feet) and then using a remote-controlled robot on a cord to reach a further 204 meters (669 feet). The dive had to end there as the cord ran out of length, although the robot sub did not seem to have hit the waterbed, suggesting it could likely go deeper.

The exploration revealed that the abyss is the deepest known underwater cave, measuring at least 12 meters (39 feet) deeper than the previous record holder in Pozzo del Merro, Italy.

After the expedition, lead diver Starnawski said he felt like a “Columbus of the 21st century,” Associated Press reports.


As you can see in the diagram above, the water only starts 70 meters (229 feet) deep into the cave. You can also see that a few areas of underwater cave are still yet to be explored. 


Since the water temperature was as low as 15°C (59°F), the suit had to be electrically heated. To make the challenge even tougher, the mud and water’s mineral content can damage diving equipment, diving suits, and human skin. 

The team also found fallen trees and other debris from the surface deep in the abyss. Marcin Jamkowski, a member of the expedition team and an adventure filmmaker, told Live Science that this suggests the cave has changed its shape over its lifetime, as the current shape of the shaft wouldn’t allow debris to fall in.


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