The Platz des Unsichtbaren Mahnmals - or in English, the Place of the Invisible Memorial – is a memorial to Jewish cemeteries. It is located in Saarbrücken, capital of the German state of the Saarland. To the visitor, the memorial is completely invisible – it only appears as a sign at the place, reading "Platz des Unsichtbaren Mahnmals".
In April 1990, art professor Jochen Gerz and several of his students began, in secrecy, to dig up cobblestones from the place in front of the Saarbrücken castle. The underside of the stones where then engraved with the names of German Jewish cemeteries, and afterwards they were returned to the place, with the inscription facing downwards. They chose the fore court of Saarbrücken Castle because a dependency of the Secret State Police, or Gestapo, was located in the castle during the time of national socialism.
Coordinates 49°13'48.584" N 6°59'28.145" E