More than half of us currently live in cities. But while urban living has become synonymous with modern life, there is a rich history behind the rise of the metropolis.

Data cruncher Max Galka has created this visualization of the history of urbanization, using data from a recent study in Scientific Data that has extensive details on historical urban populations from 3700 BCE to 2000 CE. You can check out an interactive version of the map, along with some more background information, on his website Metrocosm.

It’s worth noting that cities are defined by different criteria in different ages. In the “ancient” period (3500 BCE to 1000 BCE) a city is defined as more than 10,000 inhabitants, in the “Classical” period (1000 BCE to 1000 CE) it is more than 100,000 inhabitants, and in the “Modern” period (1000 CE onward) it is more than 1,000,000 inhabitants.

Although it is debated, it would appear "urbanization" starts in around 3700 BCE when Sumatran civilization spawns the city of Eridu. Over the next two millennia, cities slowly begin popping across the Middle East, where they eventually reach China.

The rate of urban settlements continues to steadily rise, through Eurasia and the Americas, until around 150 BCE when a flurry of cities sparks off in Europe, particularly around the Mediterranean and through the Roman Empire. As more empires come and go, the map becomes increasingly busier as the time ticks on, but perhaps the most noticeable change is around 1850 to 1900 CE when the Industrial Revolution sends the map into hyperdrive.