structural:reformatting, stylistic:style_transfer
Marajoara culture

The Marajoara culture flourished on Marajó Island at the mouth of the Amazon River in northern Brazil between 800 and 1400 CE. The Marajoara consisted of a complex society that built mounds and constructed sophisticated settlements. The indigenous people of the area adopted methods of large-scale agriculture through the use of terra preta, which would support complex chiefdoms. Studies suggest that the civilization housed around 100,000 inhabitants.