On Thu, 5 May 2016, Noel Chiappa wrote:
If you want to see a great example of why it was
important, check out the
so-called 'Berlin Tunnel':
https://en.wikipedia.org/wiki/Operation_Gold
http://www.fas.org/irp/cia/product/tunnel-200702.pdf
Many thanks - that is indeed an outstanding project and especially
the original report is a better reading than most books on
such stories. They really transcribed a huge amount of data
and everything manually...
One does not really want to know what is possible (and done)
today - where there is no need to dig tunnels any more ;-)