It’s early morning. There’s a heavy dew. The air carries the musky scent of late summer, while thick grass smells sweet from its recent cutting. Emerald dragon flies dart about, chasing each other or perhaps a meal. To the west, the Gateway Arch rises between the Mississippi and St. Louis. It’s rush hour there and undoubtedly noisy.
Where I am, at Cahokia Mounds State Historic Park and World Heritage Site in Collinsville, Illinois, it’s quiet. But it wasn’t always so. A millennia ago this was home to 20,000 people. Their story reminds me of the one I listened to at Chaco Canyon. One would swear the park rangers at each site had collaborated.
Like Chaco, Cahokia grew from small beginnings around 800 CE to a sophisticated, complex culture that reached its pinnacle in 1150. Then, by 1300, it had been all but abandoned. None of the archaeologists can tell you with certainty why.
Cahokia evolved thousands of years ago from hunter-gatherer clans who first entered the Mississippi flood plain scientists call the American Bottom, a stretch of land from Alton, 20 miles north, to Chester, 60 miles south of St. Louis. When the people began cultivating maize, they began living in pit houses, which morphed into small villages of thatched huts.
The periodically flooding Mississippi — like the Nile — renewed the rich alluvium, increasing crop yields. Dense forests abounded with game. It seemed an idyllic place and, for four centuries, it was.What developed was a culture in which, scientists speculate, the chief was considered the brother of the sun. Called the “Great Sun,” he sat at the top of a well-defined social order, supported by a hierarchy of lieutenants. If this sounds like Chaco culture, there are remarkable similarities.
Cahokia became the cultural center of a civilization that included perhaps a couple hundred outliers, from small farming villages to intermediary religious and commercial centers to Cahokia itself. Although the site was named after the Cahokia tribe of the Illiniwek confederacy, they did not build the mounds. They were late arrivals to this area, showing up in the 1600s. That raises the question of who actually did build what has been called the largest pre-European community north of Mexico?
Whoever the people were, they constructed mounds, as many as 120 over the six-square-mile area comprising Cahokia. Most are platform-type mounds, on top of which there is evidence buildings stood. There are conical mounds; those excavated indicate these were for burials. And there were ridgetop mounds, longer than wide, and aligned in specific ways. The city was laid out so its center lines corresponded to cardinal compass points as well as astronomical events — solstices, equinoxes, and lunar standstills.
At the west end of the city, the people built a solar calendar, consisting of a 400-foot-diameter ring of equally spaced tree trunks. A single trunk stood in the exact center of the circle. From this point, sun priests could determine the exact moment of both summer and winter solstices. Over four centuries, this “solar instrument” was rebuilt five times. Archaeologists call it Woodhenge, although I chafe at the comparison to England’s Stonehenge.
The largest mound is called Monk’s Mound, so named because French Trappist monks built a house there in the early 1800s. The mound, which has four terraces, is 100 feet high, 1000 feet long, and 700 feet wide. Its base of 14 acres is larger than the base area of Egypt’s Great Pyramid of Cheops. It’s alignment is only six degrees east of true north.
Monk’s Mound was built over an estimated 30-year period by people who used only stone hoes and who carried earth from borrow pits to the mound in baskets or bags of one-cubic-foot capacity. What makes this accomplishment astonishing is the mound has been reckoned to have between 22 million and 26 million cubic feet of volume.
The Great Sun resided on top of the mound in a palace that served as home, court, and temple. People could only climb the ramp or stairs to the top on invitation.
At some point, leaders decided the center of power needed protection. Perhaps they just wanted privacy from the masses surrounding the mound. They had a two-mile-long palisade constructed around Monk’s Mound and the Grand Plaza. It also included two nearby mounds — one called Roundtop, thought to be a burial mound, and Fox, a platform mound thought to have a mortuary temple.
The palisade was comprised of around 18,000 oak and hickory logs, each a foot in diameter and 15 feet long. Over a period of 150 years, the palisade was rebuilt four times. Its wall may well have been plastered in clay to protect it from moisture as well as fire. There is no evidence against whom the palisade protected the chief and his lieutenants.
This point of the Cahokia story bothered me the most. On my first visit to Jamestown Settlement in Virginia, the palisade was made from 10-inch diameter logs. When I returned several years later, conservators had rebuilt the palisade from sawn planks. I asked why the change. The answer — when the English arrived, there were few trees of 10-inch diameter. Most were six to eight feet in diameter and require sawing to construct the stockade. That made me wonder: how big were trees five hundred years earlier? And how could late stone-age people cut and shape primal forest trees of the dimensions the English encountered?
Over the years, archaeologists have interpreted the artifacts they’ve found at Cahokia. Their interpretations are authoritative, although they concede to having excavated only about one percent of the site. Much evidence has been lost over centuries after Europeans arrived. They leveled some mounds to be used as fill — probably to level the borrow pits from which the mounds were built. They plowed and planted and built houses. The land has been so altered, we may never know the complete story.
Like Jamestown and other historical sites, the story of Cahokia will change as scientists excavate, evaluate, and interpret artifacts as yet unseen. It’s a part of the science that drives people to it — the thrill of discovery and the satisfaction of adding to our understanding of our past.
Cahokia Mounds has an exceptional interpretative center filled with artifacts and informative panels. Its best feature may well be the re-created Cahokian neighborhood with life-size models depicting daily life from grinding corn to striking projectile points to passing an afternoon in the sweat lodge.
There’s much to see at Cahokia Mounds; mounds spaced sufficiently far apart that a day’s visit gives the visitor a thorough workout. There’s even more to learn and contemplate while you explore the interpretive center.
Information at cahokiamounds.org.