[dspeyer]

So Undertown does exist?

[dkuntz2]

Kinda. While Butcher fictionalizes is, and expands on the truth, there are many tunnels throughout the city, and it's possible to traverse most of the loop underground.

Plus there's good ole Wacker drive...

[jgroszko]

And it's always exciting when those tunnels flood... http://en.wikipedia.org/wiki/Chicago_flood

[Moto7451]

While visiting Chicago earlier this year I found that a ton of great bars exist under on the lower level. Definitely worth visiting/seeing.

[vxNsr]

Hmm... I always thought it was hanging out with that sixth borough