tiefkeller is an artistic work by Kathrin Graf and Bettina Marx, who create spatial installations in a brick cellar in the Südstadt district of Bonn. Inspired by scientific or private collections, the duo develops works that interweave contemporary artworks with collection exhibits.tiefkeller aims to address both the art-interested and the public that is not interested in art to create new, sensual levels of reference between the rooms, works of art and collection pieces.