Over the upscale Berlin District of Grunewald perched a mysterious fortress, crowned by four white domes: the devil’s mountain. The Field Station was built by the allies during the Cold war as a listening station. Some 250 miles behind the enemy lines, the West was able to eavesdrop on the operations of the Soviet ideal. In vain they tried to block the eavesdropping. What are the features that make the former espionage system still fascinating for visitors?