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.
Poenari Castle Poenari Castle (] ), also known as Poenari Citadel ("Cetatea Poenari" in Romanian), is a ruined castle in Romania, notable for its connection to Vlad the Impaler. Access to the citadel is made by climbing the 1,480 concrete stairs.