Hopewell Ceremonial Earthworks, United States of America

The huge squares, circles and octagons are geometrically precise and align perfectly with the cycles of the sun and moon. 

The Great Circle Earthworks was a place of gathering and ceremony. A monumental gateway nearly 200 feet wide leads to the interior of the circle, where visitors will find Eagle Mound, named for its symmetrical, somewhat winged shape.

The Octagon Earthworks is made of two geometric enclosures: a large circle enclosing 20 acres, and an even larger octagon enclosing 50 acres, connected to one another by an avenue.

While it’s not possible to say with certainty why the Octagon Earthworks was built, the alignments of the rising and setting of the moon over its 18.6 year long cycle suggest shared beliefs.

Built on a steep bluff overlooking the Little Miami River, Fort Ancient features miles of trails, earthen embankments and hidden astronomical connections. 

Items made of materials sourced from areas as far away as the Rocky Mountains help paint a picture of the importance of Fort Ancient as a gathering place. 

Mound City consists of 25 mounds of various shapes and sizes enclosed by a low wall in an area just over the size of 10 football fields. There are two gateways—one on the eastern side, and one on the western. 

The Hopewell Mound Group forms the general shape of a parallelogram, with a Great Enclosure that measures 1,800 feet on the east and west sides and 2,800 feet on the north and south sides.

The Hopeton Earthworks feature alignments to the summer and winter solstices within one degree. In addition, certain measurements within these huge shapes exactly match those in other Hopewell earthworks across Ohio.

The High Bank Works are located in a nearly 200-acre field near the Hopeton Earthworks and Mound City. The large circle at High Bank has the same diameter as the Observatory Circle in Newark. 

The three shapes that make up the Seip Earthworks—two enormous circles and a square—were likely large gathering places of great significance, as is evidenced by their divine geometry and archaeological contributions.

The three-shape arrangement of the Seip Earthworks shows up in several ancient earthworks sites in Ross County, Ohio. Extraordinarily, these shapes all have the same dimensions.