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 (ship) teenagers and young adults. One of the two original owners was Detlef Soitzek, who had sailed with the Norwegian anthropologist, zoologist, ethnologist and adventurer Thor Heyerdahl on his "Tigris" expedition in 1977/1978, and suggested to name the ship after the famous researcher and adventurer. The ownership of the ship was subsequently turned over to an association. From spring to fall, "Thor Heyerdahl" sails mainly the Baltic Sea and participates in international sail training events. In winter, the ship has repeatedly crossed the Atlantic Ocean and sailed in the Caribbean, especially as "classroom under sails" with teenage crews. Thor Heyerdahl (ship)