Planinsko polje is a typical karst field with 11 km2 surface. It is exposed to periodical floods of the Unica river.  But those  who know its waterways through the karst can rightly call it ''The River of Seven Names'', because every time it apears on the surface it has a different name.  On Planinsko Polje it is called Unica river, which flows from Planina cave and slowly meanders to the sinkholes on the other side of the field. Planinsko polje is  dry most of the year, but nevertheless it is subject to regular annual flooding, mostly in spring, autumn and winter. At these times the polje becomes a periodic lake and offers extraordinary views. During the dry season it enables fishing, paddling, cycling or hiking.