The Underground Booty Squad
Under the near south side of St. Paul, there is a maze of walking-height sewer tunnels. At one time, there was a direct connection from a nearby drain, but it has recently been walled off. We haven't found another way in yet but it's probably not worth it since the tunnels pretty much resemble the more extensive W. 7th Street labyrinth. And because sewers stink.
-Tunnelcity, 2004