From the elevated platform of an adjacent Chicago Transit Authority station, the new headquarters of the Chicago Park District appears as a shimmering two-story disc set on a blanket of grass, its platonic roundness interrupted only by a set of parallel brick walls that slice through the building. Formally, this latest work of John Ronan’s is defined by these two moves—the circle that bounds it in plan and the masonry walls that cut across that circle at uneven intervals—and much architectural interest derives from their interplay throughout the 78,000-square-foot building.

An opening in the building’s curved exterior marks its entrance. Photo © James Florio, click to enlarge.