The Kon-Tiki Museet has what's left of Kon Tiki, the ship that Thor Heyerdahl used to prove his theory that south americans could have reached Polynesia. He constructed the boat out of materials that would have been available at the time, mostly balsa wood.There is some controversy about what he proved in his successful transit, though, since he started his journey with a 50 mile tow out of the South Pacific gyre, which would have taken him north instead of west. The museum didn't say much about that.