The Dachstein-Rieseneishoehle ice cave is amongst the largest in the world. The ice, in parts 25 metres thick, grows in winter but retreats in summer in a delicately balanced annual cycle. There are a number of huge chambers which are included in the guided tour one of the largest being King Arthur’s Dome which is 120m long, 50m wide and 20 m high. The Parsifal’s Dome contains a massive ice stalagmite called Gralsburg or the Castle of the Holy Grail. The climax of the trip is the descent into the Large Ice Chapel from Tristan’s Dome, the floors, ceiling and walls of this room are all covered in amazing display of sheets of ice.