The Kleinmachnow Tunnel and the Arrest of Harry Seidel
The betrayal of a 70-metre tunnel into Kleinmachnow ended with the capture of the famous escape helper Harry Seidel, who was sentenced to life imprisonment in a show trial.

In October and November 1962 the brothers Boris and Eduard Franzke and three other helpers dug a tunnel from a building site near Neuruppiner Straße in Zehlendorf towards the house at Wolfswerder 29 in Kleinmachnow, on GDR territory. At about 70 metres it was the longest tunnel they had dug. Harry Seidel, a former cyclist and one of the most active escape helpers, joined in early November.
Under time pressure the breakthrough was made on 14 November 1962 before the house was reached. Seidel volunteered to climb out into the garden and fetch the refugees. The Stasi had been informed and was waiting: Seidel was seized, but managed to shout a warning so the others could retreat through the tunnel. An explosive charge laid along the tunnel route failed to go off because its cables had been cut.

Six weeks later Seidel stood trial before the GDR Supreme Court and on 29 December 1962 was sentenced to life imprisonment. In 1966 the Federal Republic bought his release. Who betrayed the tunnel remains unclear.
Sources
- Tunnel Wolfswerder 29TF-Mapping (Institut für Europäische Ethnologie, Humboldt-Universität Berlin)
- Pfingsttunnel 1962, Gedenktafel (biography of Harry Seidel)Museen Treptow-Köpenick / berlin.de
Spotted an error, or know more about this story? Email us a correction or addition
Related escapes
26 January 1962
The Collapsed Tunnel under Wollankstraße Station
Students tried to dig from the bricked-up arches beneath Wollankstraße S-Bahn station into East Berlin, but the tunnel collapsed under the platform and was discovered before anyone could escape.

21 March 1962 – 27 March 1962
Heidelberger Straße Tunnel and the Death of Heinz Jercha
Dozens of East Berliners escaped through a tunnel under Heidelberger Straße until a Stasi informer betrayed it; escape helper Heinz Jercha was shot in an ambush and died after crawling back to the West.

7 August 1962
The Betrayed Kiefholzstraße Tunnel
Several escape-helper groups joined forces on a tunnel to a small house on Kiefholzstraße for a planned mass escape, but a Stasi informer among the couriers betrayed it and dozens of would-be refugees were arrested.
6 October 1962
The Second Heidelberger Krug Tunnel to Elsenstraße
A second tunnel from the Heidelberger Krug pub brought a tailor couple to the West in their pyjamas, but an informer tipped off the Stasi within hours and an escape helper was shot and captured.
