As the brightest jewel in Wieliczka's crown, the caves were proudly displayed to visitors, for whom a special railway was built. Unfortunately, the lure of these spectacular polycrystals was so great that many have been removed over the years.

The largest of them, with straight-edges measuring from 20 up to 50 centimetres long, can be found in Vienna and in museums around the world. Another threat to the caves is posed by moisture which gradually dissolves and undermines the crystals.

In order to safeguard what remains, this part of the mine has been given the status of a National Park; a geological reservation where both humidity and visitors are carefully controlled.

The two grottoes with their unique treasure are so far the only true caves to have been encountered in the mine. All the other 2000 or more chambers and galleries and over 250 kilometres of corridors and shafts were excavated by man. Can Nature have created more caves in Wieliczka that we have yet to stumble upon?