Ohio celebrates its first UNESCO World Heritage Site

The big picture: The Earthworks are a network of mounds built near Newark and across Southern Ohio.

• They were built between 1,600 and 2,000 years ago by the Hopewell Culture.
• The National Park Service and Ohio History Connection now maintain the sites.

What they're saying: "Their scale and complexity are evidenced in precise geometric figures as well as hilltops sculpted to enclose vast, level plazas," reads a description on the UNESCO website.

• "There are alignments with the cycles of the sun and the far more complex cycles of the moon."

What's happening: Free events are planned at four sites.

• Fort Ancient Earthworks & Nature Preserve, Oregonia: Programs and tours 9am-6pm Saturday and Sunday. Commemoration begins at 11am Saturday.
• Tremont Library, Upper Arlington: Ohio History Connection presentation 6:30pm Wednesday. Registration required.
• Hopewell Culture National Historical Park, Chillicothe: Tours 9am-noon Saturday, Oct. 14. Commemoration begins at 1pm.
• Great Circle Earthworks in Heath and Octagon Earthworks, Newark: Tours and programs 9am-4:30pm Oct. 15. Commemoration begins at 1pm at Great Circle.