John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Examining swelling urban borders over the past 100 years.
To get a clear picture of the Big Banglike expansion of the world's largest metropolises, look no further than "The Age of Megacities," an engaging Esri project that shows urban borders swelling over the last 100 years.
As noted on the wonderful site Maps Mania, the Esri team has selected 10 international cities to show the wind-whistling clip of modern development. For instance, here's the urban extent of Chicago in 1915:
And both red and orange areas mark the extent today:
The site includes brief explanations for how each city bloated to its mega-size, including this primer on Chi-Town:
In the mid-19th century, railroads began to take the place of slower, costlier steamboats for transporting goods in the U.S., while waves of pioneers headed for the newly acquired Oregon Territory. Chicago became a railway hub connecting the natural resources of the west with the industrial centers of the east. The city’s population more than tripled between 1850 and 1860, and growth has continued steadily since then.
The entire project is worth perusing, though here are a few more highlights. Urban Tokyo in 1972...
...was a virtual village compared to modern Tokyo:
And Mexico City was but a puny speck in 1970...
...when set against the land-gobbling metropolis of today: