A large drain on the Minneapolis side of the river, this tunnel runs for alsmost 10 blocks before the final dropshaft, with shallow tunnels above. It was likely a combined sewer outfall until the 1930s, and has a number of odd sewer-related features. The most interesting featurs of this drain are mostly near the entrance, and include the unique amphitheater structure (which entombs at least one additional tunnel outfall), the overflow pit, slide, and stairway. The rest of the drain is faily generic concrete arch tunnel with a bit of wildlife and a few side tunnels. The inscription above the entrance is somewhat readable as M 1921 S, and may have originally been MPLS 1921.
This odd stairway encases the entrance to another old sandstone tunnel, probably another former sewer.
The overflow pit near the entrance. A headless TCDrainer checks out the lower level pipe to who-knows where. This may still be an active sewer diversion, which overflows to the river during high storm flow. A manhole out front is almost at river level, but we didn't pop it due to the large number of fishermen hanging out at the entrance.
The impressive stone slide and stairway shortly after the overflow pit.
Side tunnels mostly lead to dropshafts up to high-level tunnels. The last photo shows "The Gate", which is a former side tunnel (possibly an old sewer outfall or construction adit) re-used as an ancient portal to hell.
This tunnel has grafitti for much more of its length than other drains in the area, perhaps due to the easy access and apparent popularity of the area for fishing. As we left two kids (probably taggers) were entering with a cheap flashlight. The "Almost There" tag was quite misleading, the actual end of the drain was much further.
We encountered a number of toads, which like to pee on people.
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