Amazon has almost no natural stone, so all buildings will be constructed from perishable materials and, if abandoned, swiftly reduced to nothing by nature. We

Amazon has almost no natural stone, so all buildings will be constructed from perishable materials and, if abandoned, swiftly reduced to nothing by nature. We only know the full extent of Mayan civilization because we found the ruined cities of stone in the middle of the jungle. The old Amazonians weren't able to build anything similar, because they lacked stone. Amazonian civilizations might have disappeared entirely. Interestingly, there is a very ancient voyage record by a certain Francisco Orellana (to be precise: his companion Carvajal), who describes the Amazon as densely settled by organized kingdoms (e.g. having uniformed soldiers). His record was considered fanciful, because "well everyone knows that Amazon is one big rainforest", but it is being reevaluated as accurate. https://en.wikipedia.org/wiki/Francisco_de_Orellana https://en.wikipedia.org/wiki/Francisco_de_Orellana https://en.wikipedia.org/wiki/Gaspar_de_Carvajal#The_Relaci%C3%B3n_and_Carvajal's_mark_on_history https://en.wikipedia.org/wiki/Gaspar_de_Carvajal#The_Relaci%...