Polynesian navigation snow. In the mid-20th century, Thor Heyerdahl proposed a new theory of Polynesian origins (one which did not win general acceptance), arguing that the Polynesians had migrated from South America on balsa-log boats. The presence in the Cook Islands of sweet potato that is a plant native to the Americas (called "kūmara" in Māori), which have been radiocarbon-dated to 1000 CE, has been cited as evidence that Americans could have traveled to Oceania. The current thinking is that sweet potato was brought to central Polynesia circa 700 CE and spread across Polynesia from there, possibly by Polynesians who had traveled
Thor Heyerdahl However, Kon-Tiki and his closest companions managed to escape and later arrived on the Pacific coast. The legend ends with Kon-Tiki and his companions disappearing westward out to sea. When the Spaniards came to Peru, Heyerdahl asserted, the Incas told them that the colossal monuments that stood deserted about the landscape were erected by a race of white gods who had lived there before the Incas themselves became rulers. The Incas described these "white gods" as wise, peaceful instructors who had originally come from the north in the "morning of time" and taught the Incas' primitive forebears architecture as well