generate questions: The first European to travel the length of the Amazon River was Francisco de Orellana in 1542. The BBC's Unnatural Histories presents evidence that Orellana, rather than exaggerating his claims as previously thought, was correct in his observations that a complex civilization was flourishing along the Amazon in the 1540s. It is believed that the civilization was later devastated by the spread of diseases from Europe, such as smallpox. Since the 1970s, numerous geoglyphs have been discovered on deforested land dating between AD 0–1250, furthering claims about Pre-Columbian civilizations. Ondemar Dias is accredited with first discovering the geoglyphs in 1977 and Alceu Ranzi with furthering their discovery after flying over Acre. The BBC's Unnatural Histories presented evidence that the Amazon rainforest, rather than being a pristine wilderness, has been shaped by man for at least 11,000 years through practices such as forest gardening and terra preta.
Who was the first European to travel the Amazon River? {sep_token} During what time did civilization in the Amazon was flourishing when Orellana made his observations? {sep_token} What was believed to be the cause of devastation to the civilization? {sep_token} How long since it's been that geoglyphs were first discovered on deforested land? {sep_token} What time period did the geoglyphs date back to? {sep_token} Who was the first European to travel the entire length of the Amazon River? {sep_token} In what year did the first European travel the entire length of the Amazon River? {sep_token} Geoglyphs dating to what period were found in deforested land along the Amazon River? {sep_token} Who is given credit for discovering geoglyphs along the Amazon River? {sep_token} For how many years was evidence shown that humans shaped the the Amazon? {sep_token}