This document provides a historical overview of the evolution of tall building structural systems from the late 19th century to the 1970s. It highlights several important milestones, including the development of steel frame construction, elevator technology, and glass curtain walls, which enabled the creation of modern high-rise buildings. The document also showcases structural innovations like shear walls, belt trusses, outriggers, and tube designs that helped architects design increasingly taller skyscrapers during this period.