There are a few large tunnels in Chicago, but for the below, I been to, none of them! The largest tunnels I been to is the 6-foot diameter Montrose tunnels.

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The 3.5 foot tunnel entering into a larger tunnel: the intersection of 52nd and Central. Central is 5600 West. 52nd must be 5200 South. Damn.

The 8.5 and 7.5 foot Pratt sewer joining the 10.5 foot Glenwood sewer. Pratt is 6800 N., Glenwood is 1400 W.

I went over to the intersection of Pratt and Glenwood on the surface 1 day, as I used to live near this neighborhood in Rogers Park. The Red Line trains goes over it. I could only find a catch basin. Ah well.

These were taken in the early 1900s, and certainly before 1957.

6.5 foot sewer in tunnel.

13 foot sewer.

And this is the book.

7.5 foot tunnel at 111st street, April 1938, heading to 1450 West of Eberhart avenue.

The intersection of 51st street and Natchez avenue, September 20, 1929.

The mayor in the Chicago sewers: Mayor William Hale Thompson, in Berteau, 4200 N., on October 23, 1930.

31st street and Albany. Albany is 3100 W. Neighborhood: South Lawndale. Is this sewer really 9'?

Broadway street 10 foot sewer, on February 18, 1927. 1268 feet south of centerline of Leland, 4700 N.

Bryn Mawr 5600 N., July 9, 1930.

Bryn Mawr, and diversion chamber of Mamora avenue looking southwest, 9.5 foot tunnel and 8 foot tunnel, December 9, 1930. Neighborhood: Jefferson Park.

What I like about this place, is, there's a place to walk/stand!

Kostner, 4400 West, in Humboldt Park, looking south, on the west side of tunnel, drain repair, March 30, 1960.

Magnolia avenue, looking southwest, showing intersection of 11 foot with 16 foot interceptor in Lawrence avenue, with 22 foot opening length at springing line. April 20, 1931. Neighborhood: Uptown.

Magnolia avenue again, 8.5 foot with 11 foot at Glenwood and Thorndale looking upstream, August 11, 1933.

Natchez avenue, curve, intersection of 52nd and Central, on September 20, 1929.