Gothic cathedrals relied on buttresses to reach toward the heavens, but even their heights were limited. Up through the nineteenth century, ten-story urban buildings were mostly rare marvels, and those that existed came with significant downsides. Their masonry walls had to be thicker at the bottom, which meant less floor space on lower levels. A classic example of this conundrum is the Monadnock Building in Chicago, built in 1891. At sixteen stories, the building was exceedingly tall for its time, but to achieve that height, the walls at the base had to be six feet thick.
