Berlin Spy Tunnel Memorial

The American spy tunnel was betrayed to the Soviet KGB by a double agent. An original part of the tunnel can be viewed in the Allied Museum in Zehlendorf.

The listening system in the tunnel. great pictures!

The "Berlin Spy Tunnel" memorial plaque commemorates a 450 m long spy tunnel that led from a US armed forces radar station in Rudow (West Berlin) to Schönefelder Chaussee in Altglienicke in the Soviet sector. The tunnel gave the American and British secret services access to the telephone cables used by the Soviet armed forces in the GDR for their internal communications. Until its discovery in April 1956, the tunnel was in operation for 11 months and recorded around 440,000 conversations on around 50,000 tape reels. A British double agent had betrayed the operation to the KGB, the Soviet secret service. However, the KGB only took action after a delay so as not to endanger the double agent.
Source: berlin.de/museum-treptow-koepenick/gedenkorte/artikel.854952.php