Czech cave explorers may have solved a 200-year-old underground mystery

Cave divers exploring a vast underground labyrinth in the Moravian Karst may have finally solved a mystery that has puzzled researchers for around 200 years: the exact location where the Punkva River begins.

The discovery was made in the flooded passages of Amatérská Cave, where explorers believe they have identified the meeting point of two underground streams. If confirmed, the finding would resolve a longstanding question about one of Czechia's most remarkable natural landmarks.

The Punkva is Czechia's longest underground river, stretching approximately 29 kilometers through the Moravian Karst, a region north of Brno known for its extensive cave systems and dramatic limestone formations.

Although researchers have long known that the river forms where the Sloupský potok and Bílá voda streams meet, the precise location of their underground confluence has remained uncertain.

That may now have changed.

According to Czech Radio, cave divers exploring Amatérská Cave in late October discovered a previously overlooked passage carrying water into the main underground stream.

The team entered the flooded cave system from the north, following Bílá voda downstream. While investigating a small side passage they had noticed during an earlier expedition, they encountered another stream flowing into it.

Because the incoming water was noticeably clearer than Bílá voda, the divers believe they had found Sloupský potok, potentially identifying the exact point where the Punkva begins.

The discovery follows years of painstaking exploration by members of the Czech Speleological Society.

The underwater passages are particularly difficult to navigate because of their narrow openings, complicated branching routes, and limited visibility.

Even experienced divers can overlook an entrance while swimming through the labyrinth.

Radek Nejezchleb, chairman of the Plánivy speleological organization, explained that the team had previously passed through the same area without noticing the incoming stream.

The latest expedition also achieved another milestone. Divers successfully navigated a narrow, approximately 50-meter passage beneath an underground chamber known as Rodeo, connecting two sections of the cave system that explorers had been trying to link since 2020.

The connection confirmed that the combined Punkva River flows through the passages farther south.

Although the divers are confident they have identified the river's birthplace, scientists still need to verify the discovery.

Researchers are preparing dye-tracing experiments to establish exactly how the two streams connect and whether their waters might begin mixing farther upstream.

The team plans to consult experts from Charles University and install measuring equipment and tracers in the underground passages during the winter.

The findings could improve scientists' understanding of how water moves through the Moravian Karst and help guide future exploration of its extensive cave network.

While the newly explored passages are accessible only to specialist cave divers, visitors can experience another part of the Punkva's underground journey.

After passing through Amatérská Cave, the river briefly emerges at the bottom of the famous Macocha Abyss before continuing through the Punkevní Caves.

There, visitors can take guided boat trips along the underground waterway, one of the Moravian Karst's best-known attractions.

For generations, tourists have traveled along this hidden river without knowing precisely where its journey began.

Now, after centuries of exploration, scientists may finally be close to an answer.