(hint..one of the most biggest caves in the world)
There are longer caves in the world, but a visit to a cave such as Postojna deserves full attention due to the diversity of shapes, expansive cave areas, stalactite and stalagmite formations and water characteristics.This unique landscape here is known as a karst. Slovenian Karst area is huge, between Vrhnika and Trieste, with Postojna in the middle, became the “classic karst”. The name “karst”, we geographers, are using to designate special limestone formations. This designation became a part of world geographical terminology.
I have visited it this summer.