The Historischer Kunstbunker is a network of tunnels cut into the sandstone beneath the Kaiserburg, expanded and climate-controlled in 1940 to protect Nuremberg's greatest art treasures from Allied air raids. The works stored here included paintings by Dürer, the stained glass from St. Lorenz, and objects from the Germanisches Nationalmuseum. All survived the bombing that destroyed most of the city in January 1945.
Tours run through the tunnels — 24 metres below ground — with guides explaining which works were stored where and how they were recovered after the war. The entrance is at Obere Schmiedgasse 52, near the base of the castle hill. Guided tours only; book in advance.