Molnar Janos Cave is a warm-water cave system under the Rozsadomb hillside in Buda. Its flooded passages are fed by the same thermal waters that supply nearby Lukacs Baths, making it one of Budapest's more unusual natural sites.
This is not a casual cave walk. The main appeal is for trained cave divers and travellers interested in Budapest's thermal geology, but even from the surface it helps explain why this part of Buda has so many baths, springs, and Ottoman-era spa sites.