Babylon took the lead with 60,000 people in 1770 B.C.
Located in Iraq, Babylon surged to prominence as the capital of Hammurabi's short-lived Babylonian Empire.
The city achieved glory again in the sixth century B.C. with the construction of the Hanging Gardens — one of the seven wonders of the ancient world.
The city is known from the Bible as a center of materialism and sin, home to the supposedly blasphemous Tower of Babel, which may have been inspired by a 300-foot ziggurat in the city.
Babylon remained a major city under various rulers until the seventh century.