Most scientists in the 1940s believed that ancient people could never have crossed the Pacific Ocean on simple rafts. Thor Heyerdahl disagreed. He thought the winds and ocean currents could carry a raft from South America to the islands of Polynesia. On April 28, 1947, Heyerdahl and five crew members set sail from Peru on a raft called the Kon-Tiki. The raft was built from nine balsa wood logs tied together with rope. It had a single sail and a small bamboo cabin. The crew had no motor and no modern navigation tools. They relied on the stars, the sun, and the Humboldt Current to push them westward. During the 101-day voyage, the crew faced storms, sharks, and huge waves. They caught fish and collected rainwater to survive. On August 7, 1947, the Kon-Tiki crashed into a reef near the Raroia Atoll in French Polynesia. All six men survived. The trip proved that ancient ocean crossings were physically possible. However, modern scientists have since used DNA evidence to show that Polynesian people actually came from Asia, not South America. Heyerdahl's experiment answered one question but raised many more.