What Fortress used as a palace and prison has the Festning tunnel running underneath it?
Akershus Fortress Akershus Fortress (Norwegian: "Akershus Festning" ) or Akershus Castle (Norwegian: "Akershus slott" ) is a medieval castle that was built to protect Oslo, the capital of Norway. It has also been used as a palace and as a prison.
Piombi Piombi ("The Leads" in English) is a former prison in the Doge's Palace in Venice. The name of the prison refers to its position directly under the roof of the palace, which was covered with slabs of lead. In winter, these slabs let the cold pass and they acted as a catalyst in the summer heat, imposing harsh conditions for inmates.