Re: in London
"Good luck doing that in London, even the pros at this make mistakes.
I remember them drilling to lay the new supports on Bridge in London (I am not allowed to name it), slight issue in that they drilled through a secret tunnel and flooded it! Not just any old tunnel either, special tunnel that links downing street to whitehall!"
Pretty close to what happened in the Chicago Flood - https://en.wikipedia.org/wiki/Chicago_flood. Putting in new pilings for a bridge, and hit a tunnel. From wikipedia: "cost the city an estimated $1.95 billion"