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
Kon-Tiki expedition The crew once used a hand-cranked emergency transmitter to send out an "all well, all well" message "just in time to head off a massive rescue attempt". The call sign LI2B was used by Heyerdahl again in 1969–70, when he built a papyrus reed raft and sailed from Morocco to Barbados in an attempt to show a possible link between the civilization of ancient Egypt and the New World. "Kon-Tiki" left Callao, Peru, on the afternoon of April 28, 1947. To avoid coastal traffic it was initially towed out by the Fleet Tug "Guardian Rios" of the Peruvian Navy, then