Giorgio A. Tsoukalos visits the ancient ruins of Puma Punka to see it's extraordinary stone work. The ancient builders of this South American site were so skilled that it's hard to believe they made the towering sculptures without the help of modern machinery! Investigators circle the globe in search of evidence in their quest to determine whether life on Earth began in outer space and if aliens influenced mankind in ancient times. Did extraterrestrial beings visit Earth and share information about technology and influence human religions?