On the Mendig "Museum Island" you will find, as well as the Lava Dome and the Lava Cellar, the Museumslay. In this open air exhibition visitors can easily imagine how the so called layer, the stonecutter, excavated the basalt lava and brought it up to the surface to be worked upon. On view is an exact replica of a smithy, a stone masons hut and a crane which was used to haul up the stones.