Chicago City Hall & County Building, Chicago

This structure essentially functions as an office building—or more precisely, two office buildings designed around light wells, one of which has its office spaces interrupted for two stories to accommodate the City Council. The primary objective was to construct an eleven-story structure that wouldn't give the impression of a typical skyscraper. This feat was achieved by doubling the size of the exterior façade, reducing the number of windows, and introducing Chicago's largest columns at the time—imposing seventy-five-foot-high, hollow columns composed of fifteen curved granite segments. The Corinthian capitals alone equal the height of an entire floor! The support for these purely ornamental elements necessitated the use of ten-foot-diameter caissons.

Designed in the Classical Revival style, the building received its official dedication in 1911. The entrance to the Chicago City Hall showcases four relief panels sculpted in granite, each representing one of the four main concerns of city government: playgrounds, schools, parks, and water supply. Upon entering the premises, visitors are welcomed by intricate marble stairways and bronze tablets that pay tribute to the historical city halls of Chicago, spanning from 1837 to the present day.

In 2006, a green roof was installed on the City Hall section of the building, serving as an experiment to study the impact of green roofs on urban heat islands, rainwater runoff, and the suitability of various green roofs and plant species for Chicago's climate. It also facilitated energy consumption comparisons with the conventionally roofed County Building.