Thor Heyerdahl (Norwegian pronunciation: [tuːr ˈhæ̀ɪəɖɑːl]; 6 October 1914 – 18 April 2002) was a Norwegian adventurer and ethnographer with a background in zoology, botany and geography. Heyerdahl is notable for his Kon-Tiki expedition in 1947, in which he sailed 8,000 km (5,000 mi) across the Pacific Ocean in a hand-built raft from South America to the Tuamotu Islands. The expedition was designed to demonstrate that ancient people could have made long sea voyages, creating contacts between societies. This was linked to a diffusionist model of cultural development.