Update: I went back and revisited the area in late July of 2021.
I suppose it seemed perfectly logical a hundred years ago when they covered up the River des Peres through the center of the city to control flooding.
The double barreled tunnel comes out unceremoniously just north of the Hill, and just south of Dogtown.
The area is still very industrial; once there were clay mines in this area for the brickyards, abut that has given over to other uses. A train had stopped on the tracks, allowing us a peaceful period to examine this civil engineering oddity.
River des Peres should be renamed River Despair, or Sewer des Peres.
CHRIS – – – I thought that the River Des Peres was buried because of the Worls’d Fair…
That too.