Planinsko Polje is a typical karst field formed in the Notranjska region. Its surface spreads across 11 km2. The bottom is rather flat and exposed to periodical floods of the Unica, which flows from Planinska Cave and slowly meanders to the sinkholes on the other side of the field.
The river occasionally overflows its banks flooding meadows and fields as well as the road connecting the villages on either side of the field during major floods. Today, roads and paths are elevated and can still be used in the case of minor flooding. In the past, people could only travel from settlement to settlement by boat during floods.
Owing to its changing appearance throughout the seasons, Planinsko Polje is interesting to anyone who likes to be in nature. The most popular forms of recreation are walking, running, cycling, riding, and skating in winter. The Unica offers opportunities for numerous water sports including swimming, fishing, and boating during floods.
This is the most northwestern location of the amethyst meadow squill (Scilla litardierei), an endemic species of Dinaric karst fields. Also found here are nesting birds, such as corncrake (Crex crex), barred warbler (Sylvia nisoria), red-backed shrike (Lanius collurio) and the common kingfisher (Alcedo atthis).