In Mietusia Cave in Tatra Mountains, there are the deepest sumps in Poland. Approximately 200m from the entrance, there are two almost parallel sequences of pits, called Great and Narrow Chimneys (Wielkie Kominy, Ciasne Kominy). At their bottoms are clear, spacious lakes - a challenge for cave divers. Although these sumps were so close, no connection between them was known.