The High-Karst Zone has the greatest extent in the territory of Montenegro. The terrain of this geotectonic unit is mainly built up of Mesozoic (Triassic, Jurassic and Cretaceous) limestones and dolomites of several kilometres of thickness. This thickness is even larger, due to the reverse faulting and overthrusting and thus repeating of carbonate series. The karst of this region is characterised by all surface occurrences and all processes characteristic for holokarst such as: karst plain, polje, uvala, sinkhole, dry-, hanging-, blind- and karstified valley, lapies, canyon, shaft, cave, resurgence, vrulja, estavelle and so on.