The "original" Karst (the limestone region of
under-ground rivers, gorges and caves) which gave its name to all
karst areas around the world, extends through a wide belt of south and
south-west Slovenia, from Ljubljana all the way to the Italian border.
Karst ia a type of terrain with a distinctive and uni-que
assemblage of landforms and hydrology arising from a combination of
high rock solubility and well developed secondary porosity, where
special super-ficial and underground features (karst phenomena)
developed and where underground (karst) water drainage is in
control. These rocks are charasteristic Cretaceous and Tertiary
carbonate deposits of shallow, warm-water carbonate shelf
environments.
A magnificent world under the Earth's surface - the stalagmite and
stalactite rich karstic underground world is already very popular,
thanks to the world-famous Postojna and Skocjan Caves. Other
best-known show caves are the Pivka and Erna Caves, Planinska Cave,
Vilenica and Krizna Cave.