There are entrances to Baradla-barlang (as the cave is known) near Jósvafo, at Vörös tó (Red Lake) and the main entrance, with a small natural history museum, is near the township of Aggtelek. One-hour guided tours start from here - stout shoes and a warm sweater are suggested, as the temperature in the caves is only about 10°C. Tours lasting several hours can also be made by previous arrangement. The main passageway of the Baradla Cave is 7km (4mi) long, with several side passages averaging 33ft in width and 22-26feet in height. They were shaped over many thousands of years, as rain and melting snow penetrated fine cracks in the sandstone to form subversive streams which in turn carved out long passageways and enormous caves.