|Made in Chicago: The Vertical City
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Two architectural practices, the balloon frame and Chicago Construction, made Chicago the world's first vertical city. Builders using the balloon frame method created a skeleton of two-by-fours covered by wooden siding. First widely used in 19th-century Chicago and still employed today, the balloon frame not only sped up the building process; it also made construction less costly.
The balloon frame was a precursor to a great Chicago innovation: the practice of attaching a façade onto a strong yet light steel frame. Though skyscrapers were born in New York, the method called Chicago Construction, developed by Chicago architects and engineers between 1880 and 1883, provided the basic structural system for building modern steel-and-glass office towers.