Final answer:
Skyscrapers, tall steel-framed buildings, became popular due to the rising value of urban land, innovations like steel girders and safety elevators, and the need for space in city centers.
Step-by-step explanation:
The rising value of land in some cities encouraged the building of tall, steel-framed buildings called skyscrapers. The invention of steel girders which supported heavier structures allowed buildings to surpass the previous limit of 10 to 12 stories of brick buildings. Alongside the development of the safety elevator, these technological advancements underpinned the skyscraper boom. New York's Woolworth Building and Chicago's Home Insurance Building are iconic examples of early skyscrapers, demonstrating the importance of limited space and the prestige of vertical growth in urban centers. Further innovations, such as the electric elevator introduced by the Otis Elevator Company in 1889, facilitated the skyscraper craze, permitting developers to construct and market high-rise real estate in the hearts of densely populated eastern cities. By the early twentieth century, zoning laws encouraged new architectural designs, like the "wedding cake" style seen in the Chrysler Building. Skyscrapers continue to symbolize the economic and cultural progress of cities throughout the 20th and into the 21st century.