Final answer:
Cities may stop expanding outward and begin expanding upward due to geographic limitations, the rising cost of real estate, and innovations such as the electric elevator enabling the construction of skyscrapers. Socio-political factors and issues like congestion and pollution also play roles, as these offset the economies of scale that attract businesses and residents to urban centers.
Step-by-step explanation:
What allows cities to stop expanding outward and to start expanding upward? Several factors drive the shift from horizontal expansion to vertical growth in urban areas. Geographical constraints, such as rivers and coasts, limit the outward sprawl of eastern cities, necessitating an upward development. The construction of the first skyscraper in Chicago, the ten-story Home Insurance Building in 1885, was a pivotal moment that showcased the potential of steel construction techniques. However, it was the introduction of the electric elevator by Elisha Otis in 1889 that truly enabled cities to grow vertically. This innovation started the skyscraper craze, providing businesses with the prestige of towering buildings and effectively using expensive urban real estate.
Urban growth is also shaped by socio-political dynamics. Leaders collaborate to influence the direction of urban development, whether by deciding where funding flows or by shifting land use regulations. Sociologists Feagin and Parker highlight a push-pull dynamic involving both structure, such as local government, and agency, including businessmen and activists, which affects the utilization of land. Moreover, quality of life considerations, such as traffic congestion and pollution, set practical limits on the desirability and feasibility of endless outward expansion, leading to a preference for upward growth in densely populated cities.
Moreover, cities embody the concept of economies of scale, concentrating economic activity to achieve higher productivity. The agglomeration of businesses close to a large consumer base and workforce drives efficiency. However, there comes a point when high densities result in diseconomies such as congestion and pollution, which challenge the sustainability of urban centers, and contribute to the tilt towards vertical expansion.