c) San Francisco

San Francisco’s metamorphosis during the California Gold Rush is a classic example of rapid urbanization driven by economic opportunity. The discovery of gold in 1848 near the American River brought a flood of fortune-seekers, transforming the city from a small settlement to a bustling port almost overnight. This period saw a dramatic increase in population, economic activity, and cultural diversity, laying the foundation for San Francisco’s future as a major global city. The Gold Rush era not only shaped the city’s history but also had a significant impact on the economic and demographic development of the entire American West.