Does the Czech Republic Have the World’s Deepest Cave?

47-year-old Polish diver Krzysztof Starnawski currently holds a world record for the deepest dive with a rebreather, at 283m. Going to such depths takes a toll on the human body. 

Starnawski has plunged into caves throughout the world, but one of the most interesting ones is close to home: the diver has been exploring a cave in Hranice, Czech Republic since 1999.

In 2012, however, Starnawski discovered something interesting. When exploring what he previously thought was the bottom of the cave, at just shy of 200 meters below the surface, he noticed a small shaft that he was able to squeeze through. After that, the cave continued deeper. 

The diver went as far as he could go, then lowered a surveying line. It reached a depth of 373 meters, instantly making it the second-deepest underwater cave in the world. The cave likely goes deeper, but at the time Starnawski lacked the equipment to prove it. 

The current record holder for deepest underwater cave is Italy’s Pozzo del Merro, a 392m-deep sinkhole northeast of Rome. 

After the discovery, Starnawski and his team received a research grant from National Geographic to further explore the cave.

In July of this year, he returned to find that the passageway he previously squeezed through had now collapsed. A probe sent below came to rest at 360m, likely do to debris from the collapse. 

On September 21, the team will again attempt to reach the bottom of the cave, this time using a custom-built probe to navigate the very bottom. 

The efforts are not without danger. Earlier this year, a member of the team, Maciej Wielowski, never surfaced after exploring a shipwreck in the Baltic sea. 

Starnawski has dedicated the new passage to his friend.