Modern technology meets history at the Mound. This site has one of the two largest conical earthworks in North America that archaeologists believe were created by the indigenous Adena culture between 800 B.C. and 100 A.D. Almost two centuries later, the U.S. Department of Energy developed the property as a nuclear research facility called Mound Laboratories. Decommissioned in 1993, today the Mound is a 306-acre business park.