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 after him, as are HNoMS "Thor Heyerdahl", a Norwegian Nansen class frigate, along with "MS Thor Heyerdahl" (now renamed "MS Vana Tallinn") and "Thor Heyerdahl", a German three-masted sail training vessel originally owned by a participant of the Tigris expedition. Thor Heyerdahl Upper Secondary School in Larvik, the town of his birth, is also named after him. Heyerdahl's numerous awards and honours include the following: Thor Heyerdahl Thor Heyerdahl (; October 6, 1914 – April 18, 2002) was a Norwegian adventurer and ethnographer with a background in zoology, botany, and geography. He became notable for his "Kon-Tiki" expedition in 1947,