Section 1
Technology Transforms Urban Life
Key Idea
As cities ran out of space, builders looked upward. New steel-frame construction, along with safety elevators, allowed for much taller buildings. This technology gave rise to the first skyscrapers, which dramatically changed city skylines.
To move growing populations, cities also developed new forms of mass transit. Electric trolley cars, cable cars, and underground subways appeared in major urban centers. This allowed people to travel quickly and helped suburbs grow, as people could now live farther from their jobs.