In the forest between Zbrosławice and Tarnowskie Góry, underground water from the "Fryderyk" adit flows into the so-called Roznos "Fryderyk", which leads them several hundred meters to the Drama River. At the beginning of the 19th century, the outflow of groundwater gained an interesting, brick setting - it was called the "Gwark's Gate".
The boats are pushed manually by the guides, the corridors forged in the dolomite are illuminated by a carbide lamp in the bow of the boat, and the guides pushing them tell a story about the miraculous properties of water drops falling from the ceiling.