The Gruska cave, or The Hermit’s cave, is a karst spring valley that begins with a 30-metre-high overhanging wall.  It was probably caused by the collapse of the cave ceiling.  Water occasionally flows down the overhanging wall, representing the source of the Gruska stream, which gave the cave its name, and locals say that during the First World War a hermit lived there for a long time, hence the name The Hermit's Cave.  The legend says that there was once a rich market here, which sank because its inhabitants ate, drank and danced on Good Friday.