Hopewell Ceremonial Earthworks

Geometry on a colossal scale distinguishes the Hopewell earthworks: squares, circles and octagons laid out with startling precision by Indigenous builders in the Ohio River country some 2,000 to 1,600 years ago. Several enclosures align with solar events and even the Moon's long 18.6-year cycle, and excavations yielded ritual goods in mica, obsidian and shell carried from distant corners of the continent. UNESCO inscribed the eight ceremonial complexes in 2023.