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
Erik Hesselberg Hamburg, Germany. He stayed in Germany when World War II began, so he could not return to Norway and started working as a decorator in Braunschweig. In 1945, he and his German-born wife, Liselotte (Liss) Güldner, relocated to Lillehammer, Norway. In 1947, Hesselberg lived in the village of Borre and worked as a painter. Thor Heyerdahl approached him and invited to become a navigator on the Kon-Tiki expedition. During the trip, he worked as an astronavigator and cartographer as he was the only professional sailor. He painted the large Kon-Tiki figure on the raft's main sail. Also, he drew sketches,