In 1947, Norwegian explorer Thor Heyerdahl and his crew of scientists sailed over 4,300 nautical miles across the Pacific Ocean, from Peru to Polynesia, on a balsa raft similar to those built by pre-Columbian peoples, to prove that the island natives could have been descended from South Americans. Their gruelling, historic 101-day odyssey led to Heyerdahl's best-selling book and this film, winner of the Best Documentary Academy Award.