The city of Chan Chan on Peru’s Pacific coast was the largest city in the Americas 600 years ago:

Located near the Pacific coast city of Trujillo, Chan Chan was the capital of the Chimú civilization, which lasted from A.D. 850 to around 1470. The adobe metropolis was the seat of power for an empire that stretched 600 miles from just south of Ecuador down to central Peru. By the 15th century, as many as 60,000 people lived in Chan Chan—mostly workers who served an all-powerful monarch, and privileged classes of highly skilled craftsmen and priests. The Chimú followed a strict hierarchy based on a belief that all men were not created equal. According to Chimú myth, the sun populated the world by creating three eggs: gold for the ruling elite, silver for their wives and copper for everybody else.

The city was established in one of the world’s bleakest coastal deserts, where the average annual rainfall was less than a tenth of an inch. Still, Chan Chan’s fields and gardens flourished, thanks to a sophisticated network of irrigation canals and wells. When a drought, coupled with movements in the earth’s crust, apparently caused the underground water table to drop sometime around the year 1000, Chimú rulers devised a bold plan to divert water through a canal from the Chicama River 50 miles to the north.

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