Ohio was populated with numerous earthworks, the Hopewell Earthworks finally being recognized as a UNESCO world heritage spot after being preserved for years by being used as a golf course. Unfortunately many of these have been lost as European settlers destroyed many of them. This continues to this day as Google is building a data center in central Ohio a top of land that was home to numerous native american burial mounds - https://www.datacenterdynamics.com/en/news/google-breaks-gro...