Editing Pre-Columbian era (section)

====Middle Archaic period====
[[File:PreColumbian American cultures.png|thumb|Major cultural areas of the pre-Columbian Americas: {{legend0|#4747a1|Arctic}} {{legend0|#50828e|Northwest}} {{legend0|#40895d|Aridoamerica}} {{legend0|#b4581b|Mesoamerica}} {{legend0|#548434|Isthmo-Colombian}} {{legend0|#b1c759|Caribbean}} {{legend0|#b94343|Amazon}} {{legend0|#8b782a|Andes}}]]After the migration or migrations, it was several thousand years before the first complex societies arose, the earliest emerging about seven to eight thousand years ago.{{citation needed|date=September 2012}} As early as 5500 BCE, people in the Lower Mississippi Valley at Monte Sano and other sites in present-day [[Louisiana]], [[Mississippi]], and [[Florida]] were building complex [[earthworks (archaeology)|earthwork]] [[mound]]s, probably for religious purposes. Beginning in the late twentieth century, archeologists have studied, analyzed, and dated these sites, realizing that the earliest complexes were built by [[hunter-gatherer]] societies, whose people occupied the sites on a seasonal basis.<ref>Gibson, John L. "Navels of the Earth: Sedentism in Early Mound-Building Cultures in the Lower Mississippi Valley." ''World Archaeology'', Vol. 38, No. 2 (June 2006), pp. 311-329. Stable URL: [https://www.jstor.org/stable/40024503]. P. 311</ref> [[Watson Brake]], a large complex of eleven platform mounds, was constructed beginning in 3400 BCE and added to over 500 years. This has changed earlier assumptions that complex construction arose only after societies had adopted agriculture, and become sedentary, with stratified hierarchy and usually ceramics. These ancient people had organized to build complex mound projects under a different social structure.