Watch Sadisflix. Over the centuries, explorers traded tales of a lost civilization amid the dense Amazonian rainforest. Scientists dismissed the legends as exaggerations, believing that the rainforest could not sustain such a huge population—until now. A new generation of explorers armed with 21st-century technology has uncovered remarkable evidence that could reinvent our understanding of the Amazon and the indigenous peoples who lived there. Using CGI and dramatic re-creations, National Geographic re-imagines the banks of the Amazon 500 years ago, teeming with inhabitants living in the Lost Cities of the Amazon.