Watch 6,000 years of people moving to cities

Humans have been building and living in cities for thousands of years. But only very recently — in the past few years — did the scales tip to more of us choosing to settle in cities than in rural areas.

According to the United Nations, 54 percent of the world’s population now lives in urban areas. That figure was 30 percent in 1950 and is expected to rise to 66 percent by 2050.

In the video below, you can watch the stunning rise of human cities, from their humble origin in the Fertile Crescent in the year 3700 BC to the boom of the past century.

The video was produced by data visualizer Max Galka, who pulled the information from a recent study in the journal Scientific Data. (You can explore an interactive version of the data on Galka’s website here.)

The data set is essentially a digitalization of two tomes tracking the growth of cities over time: Four Thousand Years of Urban Growth: An Historical Census, by the historian Tertius Chandler, and World Cities: -3,000 to 2,000, by George Modelski, a political scientist.

The authors of the Scientific Data report note their data set is “far from comprehensive.” It has a bunch of limitations: Chandler and Modelski used slightly different definitions of cities, and there are big, centuries-long holes in the data. That said, “These two volumes are the only global-scale compendium of urban population pre-1950,” the authors note. So they’re a good starting point to build a computerized record of the spread of human cities.

And the authors hope the data set, which was shared publicly, will be put to some good use.

“The ability to geolocate the size and location of human populations over time helps us understand the evolving characteristics of the human species, especially human interactions with the environment,” they write.

They also hope new contributors will add to it, to make it more complete. The data set could also be used as “a foundation to build a richer record” of how humans have altered their environment and clustered in cities, they write.

Or it could be used to make cool visualizations, like you can see above.

(Data via Four Thousand Years of Urban Growth: An Historical Census)