The name karst was the original name for the sterile, hilly country in Slovenia to the east of Trieste. Today, the term is used internationally for landscapes which present the following special characteristics: far-reaching loss of surface water in the karst region, large springs on the edge of the region and the presence of caves. The necessary conditions for karst are:

• water-soluble rocks such as carbonates (limestone, dolomite) or gypsum
• water, both for dissolving and carrying away the dissolved material
• relief, so that the water can flow
• time, much time is necessary. Pure water can only dissolve a small amount of limestone, as opposed to water that has been exposed to air or carbon dioxide by flowing through soil. This water is acidic and, therefore, aggressive to limestone.

In mountains with a limestone basement exist so-called karstic furrows. These are numerous channels and grooves formed over many thousands of years which demonstrate the dissolving power of water. The Dolinen are a relatively widespread karstic phenomenon of sinkholes varying in diameter from several to one hundred metres. There are also many karst regions characterised by a complete lack of such surface water flow in which the structures mentioned above are not present or completely hidden by thick vegetation.
Where are the karst regions in Switzerland located? As shown on the map, they are mostly located in regions near the Jura Mountains and in the (northern) Alps. The total surface area is about 7900 km² (Jura 2700 km², Alpd 5200 km²), and corresponds to 19% of Swiss territory. This value is clearly less than the European average value of 29%.