Open every day. Containing 20 km of underground galleries, chambers and corridors, up to 50 meters high in places. Tours begin with a train journey into the cave system through several chambers before visitors get off and do a guided walk through stalagmite studded caverns. The train then returns you to the surface. The whole tour lasts 90 minutes. Tall travelers beware - the cave ceiling is very low in many parts of the train journey with sharp protrusions from the cave walls, and the train runs quite fast, so keep all bodily limbs (and children) well inside the moving vehicle! Other longer and more strenuous tours ("Underground Adventures") are available to groups of 2-50 people. The caves are damp and chilly (10 C year round) so appropriate shoes and clothing should be worn. €25.80/20.60/15.50 adult/student/child. Start of guided tours is at 10.00, 12.00, 14.00 from October to April and on every hour on the hour between 9.00 and 18.00 from May to September.