Spiro Mound Group - Credit: Wikimedia Commons
Spiro Mounds (34 LF 40) is an Indigenous archaeological site located in present-day eastern Oklahoma. The site was built by people from the Arkansas Valley Caddoan culture. that remains from an American Indian culture that was part of the major northern Caddoan Mississippian culture. The 80-acre site is located within a floodplain on the southern side of the Arkansas River. The modern town of Spiro developed approximately seven miles to the south. Read more on Wikipedia
Source: en.wikipedia.org