The nation’s first zoning ordinance became law on July 25 in New York City, restricting the height and mass of skyscraper projects and challenging architects to work under new “setback” rules. Some of the regulations had been first proposed at a City Plan Conference in 1912, but the construction of the then-gargantuan Equitable Building three years later had sped up reform efforts. The Equitable, designed by Ernest Graham, of the Chicago architecture firm of Burnham and Root, rose thirty-nine stories and threw whole blocks of lower Broadway into shadow. At the time, it was the most massive office building in the world— A CITY IN ITSELF , said one newspaper headline, HOUSING 16,000 SOULS . Its 1.2 million square feet of floor space sat on less than an acre of land.

Under the 1916 setback law, a structure’s floor area could be no more than twelve times greater than the area of its building site; the Equitable’s had been thirty times as large. Skyscrapers that followed it would assume all kinds of ingenious shapes. Chicago, the birthplace of the skyscraper, never fettered its developers with anything like New York’s elaborate zoning laws, and buildings at least as massive as the Equitable continued to flourish there.