“There being one of these [mounds] in my neighborhood, I wished to satisfy myself whether any, and which of these opinions [regarding the identity of the Mound Builders] were just. For this purpose I determined to open and examine it thoroughly.” – Thomas Jefferson

When most people think of “ancient American civilizations,” the Aztec, Maya, or Inca cultures probably come to mind immediately, because the societies in Mesoamerica have left behind permanent structures for millions of visitors from around the world to see each year. At the same time, however, from about 1000-1500 CE, an equally complex culture formed along the banks of the Mississippi, Missouri, and Ohio Rivers. From Red Wing, Minnesota to Greenhouse, Louisiana, and from Spiro, Oklahoma to Macon, Georgia, societies built impressive mound structures that served as ritual platforms, burial sites, and residences for the elites. These mounds also served as the focal points of urban areas of varying sizes that were connected to each other through trade and ideology, forming a culture that modern historians have since designated the “Mississippian culture.”

Given Europe’s familiarity with the Mesoamerican civilizations and lack of knowledge about North America, when white settlers first came upon the giant mounds and earthworks dotting the North American landscape in the 17th and 18th centuries, they couldn't imagine that the local natives were capable of such advanced technology and masterful engineering. In fact, when President George Washington sent adventurer and military strategist Rufus Putnam to survey the land at the convergence of the Ohio and Muskingum Rivers in southeastern Ohio for settlement, Putnam reported that he’d discovered an impressive walled earthwork complex near present-day Marietta that was obviously the breastwork of an ancient fortress built by some long-forgotten ancient civilization. Like others of his time, Putnam couldn’t conceive that indigenous Americans had at one time reached such an advanced level of cultural and technical sophistication.

However, even as these elaborate earthen complexes have ultimately yielded tens of thousands of artifacts, including earspools, panpipes, effigy figurines, engraved copper gorgets, head plates and headdresses, bone hair pins, silver and copper tablets, game stones, greenstone axes, flint blades, and zoomorphic effigy vessels (to list just a few), they have really only added to the mystery and intrigue surrounding the ancient peoples who built the mounds. It has only been recently that modern archaeological, anthropological, and historical methods were utilized to create a somewhat accurate image of the Mississippian culture’s reach and importance in the wider contexts of American and world history. Today, historians have a much better understanding of many aspects of Mississippian culture, including its chronology, the religion of the people, urbanization, and how the people lived, and the fact that there were fully functioning complex societies that had sophisticated forms of government and long-distance trade networks.

The mounds they made, which continue to serve as standing testaments to their extraordinary accomplishments, continue to be studied by experts who still have plenty of questions about the societies that produced them. But one thing’s for sure: with no evidence of a written language and a high probability that the groups spoke different languages (based on the earliest lingual patterns encountered from each region), what the Mississippian culture accomplished in the span of a few centuries is nothing short of phenomenal.