Grave Creek Mound Archaeological Complex is at 801 Jefferson Ave. via SR 2. Considered the largest prehistoric Native American burial mound of its kind, the 69-foot mound was built more than 2,000 years ago and was originally surrounded by a moat. The Delf Norona Museum contains a collection of artifacts of the Adena period (approximately 1000 B.C. to beyond A.D. 1) as well as rotating cultural exhibits. Also in the complex is an interpretive garden and a research facility where visitors can observe an archeological lab.