The Cahokia Mounds:

Cahokia Mounds State Historic Site, the largest prehistoric mound center in North America and a UNESCO World Heritage Site, was confirmed by Warren K. Moorehead's 1921–1927 excavations to be constructed by indigenous peoples between A.D. 1050 and 1350. Originally containing over 100 mounds used for rituals, elite residences, or tombs, the site faced destruction from urban development before Moorehead's work. His investigations, blending 19th-century techniques with contemporary methods, preserved the legacy of Cahokia while navigating social pressures. Reissuing his findings provides insight into this critical archaeological effort and the prehistoric civilization that built it.

Moorehead, W. K., & Leighton, M. M. (2010). The Cahokia Mounds: The Cahokia Mounds, 97–188. https://doi.org/10.2307/jj.30347142.8