The Underground Booty Squad
A short distance up from its outfall, this drain soon splits into tunnels of all different shapes - triangular, coffin-shaped, and square. The square tunnel leads to a series of dead ends similar to the West Seventh sewer labyrinth. One abandoned tunnel follows under West Seventh for about a mile. Farther up the main tunnel, there are more of the drop shaft waterfalls that characterize St. Paul drains.
-Tunnelcity, 2004