Artist's conception of Etowah Mounds in Cartersville, Georgia.
Mound-building remains one of the greatest mysteries of early Native American culture in the Southeast and the expansive valleys bordering the Mississippi, Ohio, and Tennessee rivers. Examiner.com recently published a concise overview of the mounds. According to the article:
Since most Indian mounds in the United States have been abandoned since 1600 AD or earlier, erosion, cultivation and exploratory excavations have radically changed their appearance from when they were in use. Visitors to historic sites, where mounds have been preserved, do not realize that they were once earthen buildings with brightly colored decorative motifs on the side. Most mounds also had large ceremonial ramps or at least wooden steps leading to the top. As a result, laymen often view the remnants of these huge structures as something akin to landscaping, rather than true forms of public architecture.
The article also notes that the mounds were built with human labor, and that the mound-building Native Americans had no beasts of burden or excavation machinery. Soil, clay, or stones were carried in baskets on the backs of laborers to the top or flanks of the mound and then dumped, and hundreds of thousands of man-hours of work were required to build each of the larger mounds.
Click here for the article.