The Inca Empire was larger than the Roman Empire at its height, yet had neither wheel nor written language.

 
Four Ayoreo men making contact with the outside world in 2004. The same men have uncontacted relatives who continue to live in their rapdily disappearing forest.
(Note: The Ayoreo-Totobiegosode are thought to be the last group of uncontacted South American Indians living south of the Amazon Basin. Roughly 300 Totobiegosode have not yet been contacted…

Report: Peru to Sue Yale for Inca Artifacts
The Associated Press
November 9, 2008
LIMA, Peru: Peru has reportedly approved a plan to sue Yale University for thousands of Inca artifacts excavated decades ago by a U.S. scholar at Machu Picchu.

 
Tiwanaku ceramic vessel in museum in La Paz, Bolivia; evidence of South Americans taking hallucinogens dates back at least to the Chavin culture, in north/central Peru, which flourished from 1,000 to 200 B.C.

 
Andean Mummy Hairs Show Hallucinogen Use Discovery News
Oct. 29, 2008 — Andean mummy hair has provided the first direct archaeological evidence […]