No one knows what happened to this 1,000 year old, lost city in America

A bustling population once lived in an ancient civilisation where East St Louis, in southern Illinois, stands today – and the reason people fled remains a mystery.

Nicknamed “America’s forgotten city,” Cahokia is the largest archaeological site in the US, and its remains are one of the country’s eight cultural World Heritage sites.

The ancient native settlement, which produced huge pyramids and giant earthen mounds, was settled around 600 AD, reaching the peak of its success around the 13th century and then disappeared entirely.

The city was built by Mississippians, a group of Native Americans, and it was a thriving multicultural environment. Architects have found that a third of its population weren’t originally from Cahokia.

You could argue it was making cosmopolitan look cool way before New York ever did.

The people of Cahokia farmed, hunted and traded, and the city played host to sacred meetings and ceremonies.

But the once-bustling city was abandoned, and while there are some theories floating around (climate change, scarcity of natural resources and flooding) the real reason why remains a mystery to this day.

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