Across the Pacific Ocean from San Francisco sits an unexpected counterpart in Shenzhen, China—a onetime fishing village of 30,000 that has grown over the last three decades into a 12 million–person metropolis with ambitions of becoming China’s Silicon Valley.

However remarkable, Shenzhen’s story is expected to be repeated. According to leading urbanists, cities across Asia and Africa are expected to undergo the same sort of radical transformation, as the world’s number of megacities—those with more than 10 million people—climbs from 23 in 2010 to 41 by 2030.

Overall, people are bullish on cities, which experts predict will house more than 70 percent of the world’s population by 2050. According to a United Nations agency, the continuing expansion of urban areas is “likely to be one of the most significant factors affecting society over the next 50 years.” In the United States alone, the trend is overwhelming: While 95 percent of the population lived in rural areas at the end of the 18th century, 80 percent of Americans currently live in metropolitan areas.

Nonetheless, it’s not easy to find consensus in the conversation. While some suggest we’re living in a “century of cities,” others propose that cities may actually lose some of their luster as the proliferation of the Internet obviates the need for physical clusters of people. And as some point to the apparent death of suburbs as a sign of the ascendance of cities, others suggest that suburbs are closing the gap on their downtown neighbors.

What’s lacking in these apparently competing perspectives isn’t intelligence but context. The story of one city isn’t the story of all of them. And, in fact, the story of American cities turns out to be different from that of Asian cities, which differs from that of African cities, and so on and so forth across the continents.

In most developed countries, cities are still growing but approaching their apex, if they haven’t reached it already. Most of the projected 18 percent urban-population growth Americans can expect to see in the next decade will be found in smaller cities like El Paso, Texas, and Des Moines, Iowa, which have more running room than more mature metropolises. Europe’s cities across the pond are expected to grow at about the same rate, from 920 million to 1.1 billion by 2030, though that growth will be uneven: London, for example, hasn’t grown much since the 1950s, and certain cities in Eastern Europe may actually see populations decline.

Overall, 80 percent of the population in Organisation for Economic Co-operation and Development member countries already lives in urban areas, which puts a cap on how much more city-centric they can become.

But across Asia and Africa, where only between 30 percent and 60 percent live in cities, you’ll find the more radical story of the future of cities.

Asia alone will see 2.5 billion people—nearly half the world’s population—living in its cities by 2025. China in particular has driven this unprecedented urban growth by taking cities like Shenzhen from obscurity and sprouting them into world-class urban destinations. In 2013, 53 percent of the Chinese population lived in cities, compared with just 19 percent in 1980.

India, meanwhile, is the next frontier, with about a third of its population living in cities today. But as the country’s total population approaches two billion, its urban population is expected to climb to double the total U.S. population within 15 years, according to projections from McKinsey & Company.

Similar growth is expected in Africa, where 60 percent of the population still lives in rural areas, but the growth of megacities—such as Lagos, Nigeria, and Kinshasa, capital of the Democratic Republic of Congo—is rapidly shrinking that figure.

What all of this means is that the disagreements over the future of cities are not really what they seem—because it’s impossible to have a single conversation about the future of cities. The world’s cities are too diverse and are in different stages of development. But something everyone can agree on is that the city is not going away.

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