Nearly a century ago, humans built skyward for the first time at an unprecedented rate. It was the age of skyscrapers.

During the half-century before 1920, the US population doubled. At the same time, the Industrial Revolution simmered, reaching a boil as America leaned into World War I and produced the machines and material to fight in Europe. After the war, the population growth and significant gains in industrial productivity led to a dramatic rise in office space needs—from 1870 to 1920, the demand for US office space increased ten-fold.