Across the road from the Gellért Baths, tucked in one of the hollows of Gellért Hill, is the Cave Church. According to legend, it used to be inhabited by St Ivan, a hermit who used thermal waters to heal the sick. Thanks to these warm springs nearby, the temperature of the church is always around 20 degrees and doesn’t require artificial heating. From the 1920s on, the cave served as a sacred place for monks of the Order of Saint Paul, inspired by a similar construction in Lourdes, and who built the first modern entrance to claim the cave as their own. The Order’s most important relic, bone fragments of Saint Paul, are kept here. The church can be visited any time except during Mass – look out for the large white cross above its location.