The Radensko Polje is the smallest of the nine most pronounced karst poljes (flat, steep-walled depressions with no outflowing streams) in Slovenia. It lies in the middle of the Lower Carniola karst region, three kilometres southeast of Grosuplje.

This area, only a few kilometres wide, includes all the typical karst phenomena, such as karst springs, caves, sinkholes, estavelles, and dry karst caves.

Estavelles – funnel-shaped hollows with a hole at the bottom – function as vent-holes in rainy periods and as sinkholes when it is dry.

The estavelles freeze over during the winter. When the water recedes underground, only broken ice remains in the hollows.