The Huellee quarry is a characteristic feature. Etymologically, the name denotes a hollow rock. Over the centuries, rough stones were broken here from a particularly abrasion-resistant stratum of Luxembourg sandstone in dangerous manual labour and were worked into millstones. A number of mills in the region are likely to have been fitted with millstones from the Huellee quarry. In the course of time, some impressive caves were formed, on whose ceilings and walls the circular chisel marks are still recognizable. When the shape of the rough stones had been cut out in the rock, the stone was “forced out of” the ceiling or wall by means of wooden wedges. To do so, the wooden wedges that had been driven into the rock were moistened. The wood swelled up from the effect of the water and generated such strong pressure that the rough stone was released from the rock.
At the end of the seventies, the Berdorf Tourist Association opened the partially-buried caves and fitted one out as an amphitheatre for cultural events.