At 55 stories, Bank of America Tower is the tallest commercial office building completed in Chicago in the past 30 years. The 1.5 million-square-foot building features a stepped center core with rippling 5-foot setbacks running up the height of the west river-facing façade. This enhances leasable space by carving out the equivalent of 14 corner offices per floor. The setbacks also accentuate the building’s verticality. The 41-foot-high marble lobby is enclosed by a cable-supported, ultra-transparent glass wall, similar to 150 N. Riverside on the opposite river bank, also designed by Goettsch Partners. The site was formerly home to The Morton Salt Building, a five-story limestone structure with formed stainless-steel spandrels completed in 1958 by Graham, Anderson, Probst, and White. The Morton Salt Building remained a fixture on Wacker Drive for 60 years. To reference the earlier Modernist low-rise, Goettsch refurbished and incorporated its original spandrels into the tower’s riverside frontage—an unusual compromise with federal and state-level historic preservation entities.