The Place of the Invisible Memorial (Platz des Unsichtbaren Mahnmals) is one of the most unusual Holocaust memorials in Europe. In 1993, artist Jochen Gerz secretly excavated 2,146 cobblestones from the square in front of Saarbrücken Castle, engraved the names of destroyed Jewish cemeteries in Germany on their undersides, and replaced them. The square looks perfectly normal — but every stone carries a hidden inscription.
The memorial can only be known about, not seen. This invisibility is the point: the memory of what was destroyed is present but inaccessible, just as the cemeteries themselves are gone. A small explanatory plaque on the square's edge tells visitors what lies beneath their feet. It is the kind of conceptual work that becomes more affecting the longer you think about it.