 Identifying the first "true skyscraper" is not straightforward, and various candidates exist depending on the criteria applied.George Post's New York Equitable Life Building of 1870, for example, was the first tall office building to use the elevator, while his Produce Exchange building of 1884 made substantial structural advances in metal frame design.The Home Insurance Building in Chicago, opened in 1885, is, however, most often labelled the first skyscraper because of its innovative use of structural steel in a metal frame design.