By some coincidence, yesterday this video popped up in my YouTube feed...
Forgotten Tunnels Under Chicago - EXPLORING The History of Chicago Tunnels
This was a turn-of-the-20th century effort to put delivery systems into more than 60 miles of tunnels beneath Chicago. It was in use for about 60 years and was eventually abandoned and more or less forgotten. Inevitably, something went wrong.
I wonder what would have happened if this had happened 30 years later, given the incompetence of the current city government.
—”60 miles of tunnels beneath Chicago”
A friend was deeply involved in the restoration after the Chicago tunnels flooded and I had a guided tour!
The video had many interesting tidbits.