Where This Mound Stands Was a City Larger Than Paris

What drove the rapid decline of the largest city of North America some seven centuries ago? Annalee Newitz takes an up-close look for Ars Technica after traveling to the outskirts of East St. Louis, Ill., this past summer to help archaeologists dig up what evidence they can of Cahokia, which at its prime in AD 1050 (30,000 people) trumped Paris in size. By 1400, its people had vanished. Environment may have played a key role in its creation and abandonment, and not just as it generally influences spirituality. As for its formation, Cahokia expert Tim Pauketat tells Newitz a celestial event, like the supernova that lit up the sky for weeks as the earthern-mound-studded city was growing in 1054, possibly triggered a movement to "found a new kind of civilization," as Newitz writes.

When the city declined and was ultimately abandoned during the so-called Moorehead phase between 1200 and 1350, there may have been droughts that taxed the densely populated area. There may also at one time have been a revolt against the elites, who possibly directed what look like theatrical sacrifices. What's clear, Newitz writes, is that Cahokia—marked in its downtown's center by the 100-foot-tall Monk's Mound—occupied a special place. One night at dusk, Newitz climbed that mound and watched a "blood red" sunset, fireflies flashing at her ankles. "With our feet atop an ancient megalopolis and our eyes on distant skyscrapers, it felt as if cities here were inevitable," she writes. "I’m not a New Agey person, but there was something undeniably magical about that." Read her full feature at Ars Technica. (More archaeology stories.)