Budapest Caving Tours
Budapest has a huge cave system under its surface (related to the fact that Budapest has several thermal baths and immense thermal water reservoirs).
Absolute Walking Tours offers a 3.5 hour tour with rock climbing and squeezing through narrow passages in Palvolgyi Cave, Budapest (the tour covers a tinier bit of the 20 km cave system, where the average temperature is 16-18 degrees Celsius) – equipment, pro cave guide provided, but not the shoes. Daily, except for Sundays and Hungarian public holidays. Min age 10 years old.