Urbanization.

The single most important influence on American architecture during the 1920s was the steady urbanization throughout the United States. The 1920 census revealed that for the first time in history more than 50 percent of Americans lived in towns or cities. By the end of the decade that figure had risen to 56 percent — or about 69 million — of which nearly 29 million lived in cities of more than 100,000. These commercial and industrial centers flourished not only on the East Coast but also in the upper Midwest, the Southwest, the far West, and Florida. Cities gave birth to skyscrapers, which required minimal horizontal space and which in their verticality suggested power, prosperity, and the latest technology. Cities also produced industrial plants, colossal movie houses, gas stations and tourist cabins (predecessors of motels) — and, by the mid 1920s, traffic jams and pollution. Thus, as these urban centers...