Built in 1902, the Ingalls Building in Cincinnati was the first reinforced concrete skyscraper in America. Standing 210 feet high, the 16-story building is still in use today. Not until after World War II, however, did concrete buildings exceed 20 stories. Higher buildings were uneconomic because then-current codes required large columns that took up too much rentable floor space. Not until the mid-1950s, when elastic design was replaced by ultimate strength design, did concrete building heights begin to rise.
Soon, the improvements in concrete structural design were matched by improvements in the material itself. In rapid succession the world's tallest reinforced concrete buildings were surpassed by even taller concrete buildings, which stand as colossal monuments to the performance of concrete a material that continually (though not surprisingly) outperforms itself, especially in high-rise construction.
Featured buildings are: Water Tower Place (Chicago), MLC Centre (Sydney, Australia), Peachtree Center Plaza Hotel (Atlanta), and the Westin Hotel (Detroit).