Mather Tower is one of the strangest silhouettes in the Chicago Loop: a narrow 1928 skyscraper rising to a slim octagonal tower above the riverfront canyon. Its upper floors are famously tiny, which is part of why the building stands out among the broader office blocks around it.
Look up from the Chicago Riverwalk or nearby Michigan Avenue Bridge to see the restored terra-cotta crown. It is a quick architecture stop rather than a long visit, but it adds a good footnote to a Loop walk focused on Chicago's early skyscrapers.