On this Native American Heritage Day, we examine a long overlooked marvel of ancient engineering

that had been tucked away beneath a golf course near Columbus, Ohio.

Some archaeologists say it's on par with Stonehenge,

but its struggle for recognition spanned decades, ending only recently,

with validation as the state's only World Heritage Site.

Stephanie Sye is back with that story.

So we're approaching the avenue, the parallel walls that connect the observatory circle with the octagon beyond.

From the ground where archaeologist Brad Lepper stands, you can't really appreciate its complexity.

It's the view from above that

reveals the site in Newark, Ohio's astonishing geometry. The octagon earthworks are composed of vast

soil mounts, a perfect 20-acre circle connecting to a perfectly symmetrical 50-acre octagon,

large enough to fit four Roman Coliseums. The intricate design mirrors

the moon's 18.6-year journey across the sky. Its central axis meticulously aligned to the spot where

the moon rises at its northernmost point. And they're not just close to being precise.

They're very, very precise.

What's even more impressive is when it was constructed.

About 2,000 years ago, the span of time we're talking about is like 1CE all the way up to 400 C.E.

That's about the time of the peak of the Roman Empire.

There are still many unknowns about who these Native American builders were.

It's a long gone ancient cultural network spread across the eastern United States that researchers now call the Hopewell.

These people lived in scattered little communities, and thousands and thousands of those

communities probably came together here, but they have left no written records.

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