What is the deepest thing in chicago?

The deepest point in Chicago is found in the Calumet-Sag Channel, where depths reach approximately 30 feet. This artificial waterway is part of a system designed to manage water flow and prevent flooding in the area. Additionally, the deepest natural feature near the city is the Chicago River, which has some sections that are also quite deep, but they do not surpass the depths of the Calumet-Sag Channel.