Autumn leaves crunch under our shoes as dozens of curious tourists and I follow the guide along the grassy embankment.
We stop at the moment when we reach the circle, which is located on an elevation formed by another wall of filled earth.
We were at the Octagon, part of the Hopewell Ceremonial Complex, a large network of hand-made mounds stretching across central and southern Ohio that were built about 2.000 years ago.
The natives would come to the Octagon from places hundreds of kilometers away and would regularly gather there for joint rituals and worship.
"Here was a ritual bathhouse or some sort of purification center," says our guide Brad Lepper, a senior archaeologist with the Ohio Historical Society and their World Heritage Program, as he points in the direction of the circle.
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I see a perfectly manicured lawn - like a golf course.
A flag on a high stick marks the hole located in the center.
The Octagon is currently used as a golf course.
All of these prehistoric ceremonial formations in Ohio were created by the Hopewell culture, a network of communities that gathered here and came from as far away as Montana or the Gulf of Mexico between 100 BC and 500 AD and were connected by numerous trade routes.
Their earthworks in Ohio consist of shapes - circles, squares and octagons - most often interconnected.
Archaeologists are only now beginning to understand how sophisticated all these engineering marvels were.
Built with astonishing mathematical precision as well as complex astronomical alignment, these are the largest geometric earthworks in the world that were not built as fortifications or other defensive structures.
And although the majority of people have never even heard of these formations, nor of their builders, it seems that things are changing in that field as well.
This year, the US government nominated eight Hopewell formations for consideration by the UNESCO World Heritage Program.
Also on the list are the Great Circle and the Octagon in Newark, Ohio, as well as Ohio's first state park - The Ancient Fort (not a real fort).
The other five are part of Historic Hopewell Park - Mound City, Hopeton Earthworks, High Bank Works, Hopewell Mound Group i Seip Earthworks.
Leper told me that the Octagon and Great Circle were once a large, unique Hopewell complex spanning 11,6 square kilometers and connected by a series of earth-walled roads.
Walking through these areas today, you can't resist the shock of their size.
The Veliki Krug, where the Museum of the Ceremonial Complex is located, is 400 meters away.
Its walls rise to a height of almost five meters and are bordered on the inside by a deep moat.
The large circle was once connected to the square and the burial ground.
Today, only one part of that square can be seen. The Octagon sprawls over a massive 30 hectares of the Observation Circle, a huge earthen circle used to gather and perform rituals of gazing at the night sky.
"You could fit four Roman Colosseums in the Octagon," says Leper.
Stonehenge would fit in the small circle that serves as a golf course today.
He adds that 2.000 years ago, the natives built these formations without modern tools, digging the earth with sharp sticks and carrying it in woven baskets on their own backs.
It is assumed, he adds, that they moved around 200.000 cubic meters of earth.
The goal of this Hopewell achievement was not simply the creation of large, profiled forms that they normally built without a hilltop vantage point to serve as an aerial view of the structures.
Above all, they incorporated a kind of hidden geometry into these structures.
Until the mounds were measured and compared, it was thought that the builders had no mathematical or geometric knowledge, especially since there were no written traces to testify to their skill.
In the end it was discovered that they were able to make precise measurements of all their works and connect them in completely unexpected ways.
Leper explains that the circumference of the Great Circle is "equal to the circumference of the perfect square with which it was connected", and that "the size of that perfect circle is equal to the area of the Observation Circle which is connected to the Octagon".
"If you were to draw a square in the Octagon itself by drawing a line that would go at alternating angles to the Octagon, the sides of that square (321 meters) would be identical to the diameter of the circle (321 m) with which it is connected," he adds.
Archaeologists are constantly finding examples of such interconnected earth formations.
According to Leper, that dimension of 321 meters, whether halved or doubled, was found at other indigenous sites throughout the country and served as a common unit of measure.
And while this geometric and mathematical knowledge of Hopewell fascinated scientists, an entirely different level of sophistication emerged when the earth's deposits were laid bare - astronomical alignment.
In the 1980s, two professors from Earlham College in Indiana, Ray Hively (physicist and astronomer) and Robert Horne (philosopher), decided to visit the Octagon and the Observation Circle attached to it.
Since gigantic monuments like Stonehenge attract so much attention, they wondered if these earthen structures were also aligned with the solar calendar.
Hiveli and Horn found no solar connections, but then came up with an alternative target: the lunar cycle.
"We thought that intentional lunar alignments were unlikely at Newark," they wrote, because while the Sun can be tracked over the course of a year, a complete lunar cycle takes 18,6 years.
In addition, the lunar cycle has been shown to coincide with the position of the Observation Dike in the Observation Circle.
There you can watch the Moon rise above the very center of the Octagon every 18,6 years.
"Astronomical alignments are only relevant and useful if they somehow connect celestial orbits and reliable systems that help us understand life itself," says Timothy Darvill, a professor of archeology at Bournemouth University who has researched both Stonehenge and Hopewell Ceremonial Mounds.
"The ceremonies held during the observation of the starry sky apparently also had a secondary function in nurturing the community".
That community and its culture are part of the subject that was sent to UNESCO.
A UNESCO site must demonstrate that it has "outstanding and universal value," says Jennifer Oltman, director of historic sites and museums for the Ohio Historical Society.
One of the criteria, as he says, is that these are "masterpieces of ingenious human creative contributions", and this is precisely where these elements related to mathematics, geometry and astronomy are significant.
The second criterion is "that they represent an exceptional testimony of the cultural tradition that produced them".
Oltman explains: "You can really learn something about people's lives and what was important to them by looking at and studying these earth formations."
The moon, for example, was very important in Hopewell culture.
Darvill told me that, in some cultures, the Sun, the Moon… are considered to have enormous power over everything that happens to us on a daily basis.
"That is why many heavenly bodies are worshiped and thus their power is justified and rationalized".
Therefore, it is very possible that the Moon was a deity for all those who came to the gatherings.
"The land we now call Ohio is home to numerous and remarkable earth formation sites carved out by the region's indigenous people thousands of years ago," says Megan Wood, executive director of the Ohio Historical Society.
Although not all such works are a concrete part of the Hopewell Mounds—an example is the historic Serpent Mound site in Peebles, Ohio, which faces the sun—Wood sees them all as "icons" of Native "cultural achievement."
Since there are no written traces left behind this culture, only earthworks and a few objects found there bear witness to the cultural heritage.
Archaeological excavations continue at some of the sites where objects such as ritual smoking pipes or small stone statues of shamans wearing bear skins and holding human skulls have been found (Shaman of Newark).
Since these were gathering places and not villages, the objects found represent the locations from which the natives traveled - pipe-shaped objects, copper plates and a knife made of volcanic glass.
In any case, after the Hopewell civilization gradually began to disappear around the year 500, other native peoples began to take care of the land.
One such group was the Shawnee tribe who called Ohio their home until they were forcibly relocated west of the Mississippi River in 1830.
"We may not be responsible for creating and building these formations, but I know my ancestors lived here and protected and respected them," said Chief Glenna Wallace of the Eastern Shawnee Tribe of Oklahoma, who believes other tribes should too. to have a role in the future protection of the Hopewell earthen formations and in the discussion of their cultural significance.
In any case, getting a UNESCO certificate is a complicated, bureaucratic process.
Although it is located on land owned by the Ohio Historical Society, the Octagon itself is under the control of the Moundbuilders Club.
The club is the owner of a unique contract that expires in 2078 and allows its visitors to go out to the mounds four times a year.
The rest of the time visitors can spend only on the parking platform and observe small parts of the property.
OHC is currently leading the process to evict the club (with compensation).
Lower courts have already ruled in favor of the historical society, but the decision was appealed to the Ohio Supreme Court.
If the OHC is not able to guarantee public access to the property, it could also affect UNESCO's decision.
Although UNESCO protection would not entail the return of land or reparations, it would still mean a much greater local presence and education about Native American history.
This means that more indigenous actors, such as the Shawnee, will be able to tell the story from their perspective for future generations.
"I just want people to know about this," says Chief Wallace.
"I want people to be able to see all this.
"I want people to be able to come here for a visit and I want people to understand that this is a cultural phenomenon. And that it is priceless".
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