Lake Calumet is the largest body of water within the city of Chicago. Formerly a shallow, postglacial lake draining into Lake Michigan, it has been changed beyond recognition by industrial redevelopment and decay. Parts of the lake have been dredged, other parts reshaped by landfill, and the surviving fragment of the lake now, with the rest of the city of Chicago, drains into the Des Plaines River and the Mississippi River basin.