Molnár János-barlang
Hungary's longest active thermal-water cave, opening at the Malom-tó pond on Frankel Leó út in Buda, a few hundred metres from the Danube. More than 6 km of water-filled passages have been mapped, with the deepest sections reaching about 100 m. The upper level is warmed by thermal springs to around 28 °C, while below a thermocline at roughly 10 m the water drops to about 18–20 °C. Fine sediment can quickly ruin visibility near walls and floor, but slow spring flow helps clear it.
depth: 0–100 m