By 2050, the United Nations estimates two-thirds of the world population will live in cities. China alone plans to move some 250 million people into urban areas with 10 million or more inhabitants by 2026.
Using the Timelapse feature in Google Earth Engine, we can witness the growth of these megacities — and really any location on the planet — over a 32-year period from 1984 to 2016.
Here's how much the world's biggest cities have grown.
New York City's metro population has grown considerably as crime rates have fallen and the city's outer boroughs have welcomed a new crop of residents.
Sao Paulo, Brazil has grown rapidly over the last three decades, surpassing Rio de Janeiro as the largest metro area. But 70% of the city lives in substandard housing developments, such as favelas.
Metro population: 21.2 million
Population density: 20,495 people per square mile
Source: New Geography
Manila, Philippines is one of the densest cities on Earth. Highways and public transportation are routinely clogged. In the poorest districts, houses sit on stilts.
Metro population: 12.9 million
Population density: 111,002 people per square mile
Source: Business Insider
Mumbai, India, has become a cultural center, mostly due to Bollywood and its status as a financial hub. IT and the larger tech sector are also booming in Mumbai.
Metro population: 20.7 million
Population density: 80,100 people per square mile
Source: New Geography
In Egypt, the metro area of Cairo has expanded to cover roughly twice the land area over three decades. It was the fastest-growing city worldwide in 2017.
Metro population: 20.4 million
Population density: 50,180 people per square mile
Source: Egyptian Independent
Dhaka, Bangladesh is the densest city on Earth. But its growth doesn't resemble that of New York or other developed cities. More than 40% of Dhaka residents live in slums.
Metro population: 18.9 million
Population density: 115,000 people per square mile
Source: Cities Alliance
Guangzhou, China displays perhaps the most impressive expansion of the megacities, particularly as China has pushed for more industry, infrastructure, and apartment high-rises.
Metro population: 44.3 million
Population density: 4,600 people per square mile
Source: Business Insider
In Jakarta, Indonesia, major industry has formed around the city's ports over the past 30 years. Its urban growth is averaging 4.4% increases annually, making its urban area the fastest-growing in Southeast Asia.
Metro population: 30.2 million
Population density: 37,460 people per square mile
Source: Global Indonesian Voices
Los Angeles, California, like many cities, is becoming an attractive place to live for millennials in search of city-dwelling. High-rises are going up to accommodate the surplus of residents for available housing.
Metro population: 13.1 million
Population density: 7,000 people per square mile
Source: Los Angeles Times
Tokyo, Japan is one of the largest metro areas in the world, but also one of its least crowded due to the large suburban region. About 75% of Japanese live in the Tokyo-area suburbs.
Metro population: 37.8 million
Population density: 4,600 people per square mile
Source: New Geography
Shanghai, China is one of the fastest-growing cities in the world. The city epitomizes China's quest to build tall buildings that intimidate and awe, as well as its growing presence as an economic superpower.
Metro population: 34 million
Population density: 119,400 people per square mile
Source: The Atlantic
