Dark, hollow, terrifying...Why should then we go into a rock hole which could be a gate to such a world? So that we can see that in fact caves are full of treasure hidden from daylight – amazing dripstone, lakes and...to meet their inhabitants. Caves were formed mainly as a result of karst formation process. Rocks made of calcium carbonate are mainly subject to this process. Water which consists of carbon dioxide penetrates cracks. With time these crack become wider and create a system of chambers and tunnels. The process of dissolving is long and lasts millions of years. The reverse process takes place when the solution circulating in these cracks is saturated as in this case the dissolved calcium carbonate precipitates and dripstones are formed in caves. In Małopolska (Lesser Poland) thousands of caves were discovered but most of them are maximum 100 m wide and only some of them are available for tourism – they are fitted with artificial lightning and a special trail has been prepared. They are found in the Tatra mountains and the Polish Jura. They are the best examples to demonstrate the wealth of the world of caves which needs, however, to be prepared before made available.