The cover, located in the Römerberg area, indicates the outline of an unfinished 13th-century residential building that was supposed to be the tallest in Germany.
Translation of the text on the cover: OUTLINE OF THE UNFINISHED LATE STAUFFIC RESIDENTIAL TOWER AROUND 1240
FOUNDATION DIAMETER 21.75m WALL THICKNESS 6m PLANNED HEIGHT approx. 45m LARGEST STAUFFIC TOWER IN GERMANY. ROLE MODELS IN THE FRENCH CROWN LAND