The building was finished in record time.

Despite the colossal size of the project, the design, planning and construction of the Empire State Building took just 20 months from start to finish. After demolishing the Waldorf-Astoria hotel—the plot’s previous occupant—contractors Starrett Brothers and Eken used an assembly line process to erect the new skyscraper in a brisk 410 days. Using as many as 3,400 men each day, they assembled its skeleton at a record pace of four and a half stories per week—so fast that the first 30 stories were completed before certain details of the ground floor were finalized. The Empire State Building was eventually finished ahead of schedule and under budget, but it also came with a human cost: at least five workers were killed during the construction process.