Cahokia Mounds State Historic Site, Collinsville, Illinois, North America
Some experts believe something particularly dreadful may have occurred at Cahokia because there are no legends, no records, and no lore among local tribes. The people who lived in the area were a native civilization believed to have been advanced in astronomy, agriculture and economics, who built massive structures and laid out a well-defined community - and then they just disappeared.
Ancient civilizations will naturally seem dim and mysterious to us today but there are usually some sort of writings, tablets, glyphs, records or tales to help archaeologists and anthropologists discern how the civilization functioned in its society. In a city that was believed to be larger than London at the time - around 1250 CE - and a powerful culture, the sudden disappearance of the estimated 10,000 - 25,000 people who thrived in the area of the Cahokia Mounds is a strange silence that can't be explained.
The remains of the most sophisticated native civilization north of Mexico are preserved at Cohokia Mounds State Historic Site. Within the 2,200 acre tract lie the archaeological remnants of the central section of this ancient settlement, named for the Cahokia subtribe of the Illinois (or Illiniwek), who moved into the area in the 1600s.
Believed to have occupied the site from around 700 to 1350 CE, the civilization was located in the floodplains of the Mississippi River, about 4 miles north of what is now St. Louis, Missouri. A U.S. National Historic Landmark and one of only 24 of the United Nations Educational, Scientific, and Cultural Organization's (UNESCO) World Heritage Sites, it consisted of approximately 6 square miles, with 120 mounds, a 2 mile log stockade wall, residential dwellings clustered around a huge level plaza, large agricultural fields on the outskirts of the city, and an astronomic calculator (named Woodhenge), similar to Stonehenge and made of wood.
Archeologists have uncovered and mapped 68 mounds, only one of which seems to have been used for ritual or sacrificial burial. The largest of these is mound number 38, Monk's Mound. Covering 16 acres at its base and at 98 feet high, it is the largest mound in North America. The four-terraced structure is believed to have held the home of the society's ruler. The first terrace, rising 35 feet above the surrounding ground, was gardened by Trappist Monks who lived in the surrounding mounds and for whom the mound is named.
Some believe the abandonment of Cahokia had to do with the depletion of natural forest resources or that the main crop, maize, was not enough to sustain the tribe's diet. If a flooding of the plain by the mighty river had occurred, it would have left skeletal remains.
If the people of Cahokia had simply moved on, why is there no evidence of them outside their original area? Artifacts, including exotic or non-local materials such as fancy pottery, copper, galena, shark's teeth, and sea shells, some with engraved designs, have been found at Cahokia from tribes as far north as Minnesota and south to the Gulf Coast, indicating trade and influence across a wide region and there is no indication that these were an aggressive or warring people. So what happened at Cahokia?
The mounds are said to be a source of powerful psychic energy and are visited by thousands each year. Woodhenge was built to indicate where on the horizon the sun and moon will rise and set at certain times throughout the year, yet it remains an unfathomable mystery, intensified by the fact that it is only one of hundreds of similar circular complexes and megalithic monuments throughout the world.
Astronomers agree that they serve as accurate celestial observatories and psychics have testified to unearthly experiences in their presence. It is believed that the formation taps Earth's energies but some ancient beliefs centered around good and evil spirits. These complexes may have been places where the sick were taken to be healed or may have served as portal dolmens to another world.
With no first hand documentation or word of mouth history, archaeologists continue their search to uncover more about the mystery behind the disappearance of the people of Cohokia.