860-880 Lake Shore Drive

A pair of identical 26-storey towers set at a right angle on the Chicago lakefront, commissioned by developer Herbert Greenwald, who had hired Mies for a smaller project in 1946 and returned with a tower-sized commission in 1948. Mies clad the steel structural frame in glass and applied non-structural black steel I-beams to the surface to keep the grid legible from outside, a device he reused at the Seagram Building. The towers were among the first residential high-rises built as steel-framed glass curtain wall, setting the template much of postwar American apartment building followed.