
The "illicit structure" in the bedrock of the castle hill provided a bomb-proof shelter for Nuremberg's world-famous art treasures as well as for a number of valuable objects from elsewhere, including:

For safety reasons, the most precious art treasures kept in museums and archives were also transferred to the Art Shelter in good time. They included:

In 1424, the City of Nuremberg - by order of Emperor Sigismund - was awarded the privilege of being the keeper of the valuable Imperial Insignia - orb, sceptre, imperial or Mauritius sword, ceremonial sword as well as the reliquaries and coronation robes of the Holy Roman Empire - "for ever, irrevocably and irrefutably". In 1796, in order to save the Imperial Insignia from Napoleon's conquering French troops, the treasures were first taken to Regensburg and then to Vienna in a secret operation.

By order of Adolf Hitler, they were brought back from Vienna to Nuremberg - the "City of the Nazi Party Rallies" - in 1938, i.e. before the outbreak of the war. They were put on show in the St Catherine's Church. In 1945, the Imperial Insignia were discovered in the Art Shelter by US soldiers and officially returned to the Imperial Palace in Vienna on 4/5 January, 1946.
Today, copies of the most important Imperial Insignia - crown, sceptre and orb - can be seen in the City Hall ("Wolff'scher Bau").