Poverty Point in Louisiana, United States

Poverty Point is a prehistoric earthenwork site featuring mounds, ridges, and a ceremonial plaza located in northeastern Louisiana, United States. The mounds and ridges on the site were constructed between the period of 1700 and 1100 BCE during the Late Archaic period and is the largest and most complex archaeological site from that time period. Evidence of the culture is present throughout the southeastern United States. As the name people who created the site is unknown, Poverty Point is named for the 19th century plantation that was in the area. 
 The function of the site is somewhat unknown but may have been used as a settlement, a trading center, or a religious/ceremonial center, or potentially acted as all three. Religious significance of the site has also been suggested, with the ridge sector likely having astronomical significance related to the solstices, and other mound sites being significant religious sites for native cultures. Further, the geometric layout of the site may have been related to a belief in sacred geometry. 
Further, there have been debates over whether people lived at the site permanently, or whether it was inhabited temporarily for certain events. Because of trash and other evidence of domestic habitation, scholars suggest that workers who constructed the site may have lived there. If so, it could have taken around 300 years for 100 people to create the site if they worked for six to seven days a month. There, of course, could have been other scenarios for how long and how many people the site needed for construction. As the site was built over multiple centuries, the process of leveling the ground to create the flat plaza and flat surfaces to build the mounds was complex and suggests a complex society. 
The site may have been abandoned due to a multitude of issues related to climate and ecology, such as temperature changes, changes in rain, and increased flooding