The Mramornica Cave has a huge chamber with a length of 93 m, a wide of 51 m and is 5 meter high. The entrance of this chamber is on a depth of 10 meters.
The cave was mentioned the first time in 1770 by Alberto Fortis (Italian, naturalist, monk and travel writer).
This cave has a rich variation of colours, stalagmites and stalactites reaching to a height of 10 meters.
Traces of human live were not found.
Place: Mramornica – (Brtonigla)