d) Home Insurance Building

The Home Insurance Building, constructed in 1885 in Chicago, is considered the first skyscraper. Designed by William Le Baron Jenney, the building was ten stories tall and one of the first to use a steel frame for structural support, a significant innovation in building design. The Home Insurance Building marked the beginning of the skyscraper era, transforming urban architecture and leading to the development of cities vertically rather than horizontally.