Cahokia has been the subject of much study due to its mysterious decline just 300 years after it sprang in to existence on a Mississippi flood plain. What happened to the city and its inhabitants has never been fully understood, but now a new research effort may finally be able to shed some light on it.
Sediment cores retrieved from a lake near to the city's location seem to indicate that widespread flooding took place in the region at around 1200 BC, the time when the previously thriving city of Cahokia took a sudden turn for the worse.
While the waters would not have been enough to completely destroy the city, they would have had a devastating impact on the surrounding farmland and settlements. With these resources gone, much of the 15,000 strong population would have been eventually forced to move on.