that's actually really amazing. i wonder if they will destroy it, or if it could possibly serve some other purpose, perhaps even tourism.
i work & live near the Canada / US border. a few miles from here in another border town called LaSalle, they found tunnels that go under the Detroit River which were used by gangsters in the 1920s. Even Al Capone himself used them. they were used to run booze back and forth during the prohibition, among other things.
fantastic peices of history, as unlawful as they may be. they are unsafe - not nearly as sophisticated as the ones mentioned in the OP, but would still be really cool to see. they had secret entrances in the basements of various buildings. damn... now i'm pretty curious to see if they are still there.
edit: this is beside the point, but anyone that knows or has been to York University in Toronto might have heard of their underground tunnel system. All of the buildings at York are connected by these tunnels, which are used by maintenance workers. My friend from res and I got into them and did some exploring a couple times. Super, super cool. Actually IIRC AT member "Sabot" knows just the tunnels I am referring to
