Die Ausstellung „Grundsteinkisten“ im Wandelgang des Historischen Bürgerhaus Langenberg ist ein langjähriges Erfolgsprojekt des Kunsthaus Langenberg e.V.
Kunsthaus Langenberg e.V. initiated a project based on the "Grundsteinkiste" (corner stone boxes): a triptych consisting of three limestones in a wooden box. He invited fellow artist to contribute their own works based on this model. More than 400 of these pieces by renowned artists such as Emil Schumacher, Günther Uecker, Georg Baselitz and many other painters, sculptors, photographers, and composers, are now exhibited in the aisle of the Bürgerhaus (Historic Town House) Langenberg. After their trip through many exhibitions, both national and international, 6.5 tonnes of art have found an exposed and permanent location where they impress visitors as a unique overview of contemporary art.