Jespa is a hole in the ground resulting from the sinking of a cave - typical karstic in shape which originated due to the collapse of the cave ceiling. There is a maintained path to the bottom which is approx. 30 metres deep. Due to a temperature reversal, one can soon feel coolness whilst descending.  As a consequence, there is a vegetation inversion as only mosses and lichen grow at the bottom, although ice and snow remain throughout the entire year. The starting point is the lodge Dom na Menini planini, requiring 20 minutes’ walking time.