It is well known that Budapest boasts about 130 thermal springs, formed in the karstic limestone upon which the Buda Hills stand and the source of its famous therapeutic spas, but what is less known is that around 30 km (18.5 miles) of caves and subterranean passages also riddle the city’s bedrock. Of Budapest’s nine known cave systems, three are open to the public and Pálvölgyi is the largest of these, stretching 13 km (eight miles) underground amid a spectacular ensemble of stalactites and stalagmites, caverns lined with gleaming crystal deposits, and stream-filled chambers. At points, fossils of sea urchins can be seen embedded in the cave roofs, dating back 40 million years old to the times when Hungary was under a great tropical ocean.
Discovered in 1904, Pálvölgyi abuts the Matyashegyi cave system; the two combine to make 18 km (11 miles) of underground passageways and form Budapest’s largest subterranean labyrinth. There’s no need for professional potholing experience to join caving tours led by expert guides, although there are steep metal steps to climb and round 0.5 km (0.3 mile) to cover, so wear sturdy footwear; dress in warm clothes as temperatures in the caves are at a constant 11 degrees C.
Szépvölgyi út 162. Take bus 65 from Kolosy ter. Open Tue–Sun 10am–4.15pm. Admission adults HUF1,300, seniors & students HUF1,000.