"Coch worked out he was to go to 45 Brunnenstrasse."

This map shows the location of the apartment where the tunnel began, at the crossroads with Bernauer Strasse. It was at 48 Bernauer Strasse that, on 22 August 1961, Ida Siekmann leapt from her third floor apartment window in an attempt to flee the East. She died from her injuries, one day before her 59th birthday and her life became the first to be claimed by the Wall. 

Google Map