Gunner Asch on Sun, 13 Jan 2019 04:34:37 -0800
typed in rec.crafts.metalworking the following:
:-)
But I believe that there is a history of tunnels having been dug to
cross the border.

cheers,

John B.

There has indeed. However..one of the additions to the "fence" is
sysmic detection units. They are quite easy to place..its a well
proven technology. Think of it as a form of "land sonar"

The tunnels have been dug in the basements of houses in urban areas to
other urban areas across the border.

Look up "Tunnel 57" about the most successful tunnel under the
Berlin wall.
And note how long it took to dig said tunnel.
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."