Question: What 1947 journey by raft across the Pacific Ocean from South America to the Polynesian islands was Thor Heyerdahl notable for?

Context paragraphs:
Kon-Tiki Nunatak: Kon-Tiki Nunatak ( ) is a raft-like nunatak, 1,300 m high, surmounting the Cooper Icefalls in the center of Nimrod Glacier, Antarctica.  It was first seen by the northern party of the New Zealand Geological Survey Antarctic Expedition (1961–62) and named after the raft "Kon-Tiki" which was sailed across the Pacific Ocean from East to West in 1947 by the Norwegian explorer Thor Heyerdahl.

Aku-Aku: Aku-Aku: the Secret of Easter Island is a 1957 book by Thor Heyerdahl published in English the following year.  The book describes the 1955–1956 Norwegian Archaeological Expedition's investigations of Polynesian history and culture at Easter Island, the Austral Islands of Rapa Iti and Raivavae, and the Marquesas Islands of Nuku Hiva and Hiva Oa.  Visits to Pitcairn Island, Mangareva and Tahiti are described as well.  By far the greatest part of the book tells of the work on Easter Island, where the expedition investigated the giant stone statues ("moai"), the quarries at Rano Raraku and Puna Pau, the ceremonial village of Orongo on Rano Kau, as well as many other sites throughout the island.  Much of the book's interest derives from the interaction of the expedition staff, from their base at Anakena beach, with the Easter Islanders themselves, who lived mainly in the village of Hanga Roa.

Thor Heyerdahl: Thor Heyerdahl (] ; October 6, 1914 – April 18, 2002) was a Norwegian adventurer and ethnographer with a background in zoology, botany, and geography.  He became 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 separate cultures.  This was linked to a diffusionist model of cultural development.  Heyerdahl subsequently made other voyages designed to demonstrate the possibility of contact between widely separated ancient people, notably the "Ra II" expedition of 1970, when he sailed from the west coast of Africa to Barbados in a papyrus reed boat.  He was appointed a government scholar in 1984.

Kon-Tiki (1950 film): Kon-Tiki is a Norwegian-Swedish documentary film about the Kon-Tiki expedition led by Norwegian explorer and writer Thor Heyerdahl in 1947, released in Sweden, Norway, Finland, and Denmark in 1950, followed by the United States in 1951.  The movie, which was directed by Thor Heyerdahl and edited by Olle Nordemar, received the Academy Award for Best Documentary Feature for 1951 at the 24th Academy Awards.  The Oscar officially went to Olle Nordemar.  It is currently the only feature film from Norway to have won an Academy Award.

Norman Baker (explorer): Norman L. Baker (born 1929) was navigator on Thor Heyerdahl's "Ra", "Ra II" and "Tigris" reed boat expeditions.  He was the co-author (with Barbara Murphy) of "Thor Heyerdahl and the Reed Boat Ra", a 1974 children's book on the expeditions.  He is a fellow and ex-director of the Explorers Club, and serves as an advisor to Fara Heim, an expedition searching for signs of Viking settlements in North America.

South Pacific convergence zone: The South Pacific Convergence Zone (SPCZ), a reverse-oriented monsoon trough, is a band of low-level convergence, cloudiness and precipitation extending from the Western Pacific Warm Pool at the maritime continent south-eastwards towards French Polynesia and as far as the Cook Islands (160W, 20S).  The SPCZ is a portion of the Intertropical Convergence Zone (ITCZ) which lies in a band extending east-west near the Equator but can be more extratropical in nature, especially east of the International Date Line.  It is considered the largest and most important piece of the ITCZ, and has the least dependence upon heating from a nearby landmass during the summer than any other portion of the monsoon trough.  The SPCZ can affect the precipitation on Polynesian islands in the southwest Pacific Ocean, so it is important to understand how the SPCZ behaves with large-scale, global climate phenomenon, such as the ITCZ, El Niño–Southern Oscillation, and the Interdecadal Pacific oscillation (IPO), a portion of the Pacific decadal oscillation.

Plastiki: The Plastiki is a 60 ft catamaran made out of 12,500 reclaimed plastic bottles and other recycled PET plastic and waste products.  The craft was built using cradle to cradle design philosophies and features many renewable energy systems, including solar panels, wind and trailing propeller turbines, and bicycle generators.  The frame was designed by Australian naval architect Andrew Dovell.  The boat's name is a play on the 1947 "Kon-Tiki" raft used to sail across the Pacific by Norwegian explorer Thor Heyerdahl, and its voyage roughly followed the same route.

Tangaroa Expedition: The Tangaroa Expedition of 2006 closely resembled the Kon-Tiki expedition sailing a balsa raft from Peru to Polynesia.  Tangaroa outperformed Kon-Tiki by having an improved sail rig and by actively using guaras (centerboards).  As such, the expedition represents a scientific continuation of Thor Heyerdahl's experiments in recreated maritime technology.

Viracocha: Viracocha is the great creator deity in the pre-Inca and Inca mythology in the Andes region of South America.  Full name and some spelling alternatives are Wiracocha, Apu Qun Tiqsi Wiraqutra, and Con-Tici (also spelled Kon-Tiki, the source of the name of Thor Heyerdahl's raft).  Viracocha was one of the most important deities in the Inca pantheon and seen as the creator of all things, or the substance from which all things are created, and intimately associated with the sea.

Kon-Tiki expedition: The "Kon-Tiki" expedition was a 1947 journey by raft across the Pacific Ocean from South America to the Polynesian islands, led by Norwegian explorer and writer Thor Heyerdahl.  The raft was named "Kon-Tiki" after the Inca sun god, Viracocha, for whom "Kon-Tiki" was said to be an old name. ""  is also the name of Heyerdahl's book; the Academy Award-winning documentary film chronicling his adventures; and the 2012 dramatised feature film nominated for the Academy Award for Best Foreign Language Film.

Supporting paragraphs: Thor Heyerdahl Kon-Tiki expedition
Answer: The "Kon-Tiki" expedition