Resava cave
The 51st longest cave in the world
2.3km · Length
Resava Cave (Resavska pećina) or Resavska Cave is a cave near Jelovac in eastern Serbia, about 20 kilometres (12 miles) from Despotovac. It is one of the largest cave systems in Serbia, with the corridors about 4.5 kilometres (2.8 miles) long.
Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).