Pre-Columbian rafts voyaged as far as Mexico and introduced metallurgy to the civilizations of that country. Some scholars and adventurers of the 20th and 21st century have asserted that the rafts and their crews journeyed thousands of miles across the Pacific to Polynesia, most notably Thor Heyerdahl who reached Polynesia on the Kon-Tiki raft. Several other people and groups have also built rafts based on prehistoric models and undertaken trans-Pacific voyages. Balsa is the Spanish word for raft. The use of rafts for commerce on the coasts of Peru and Ecuador, from northern Chile to southern Colombia, continued until the late 19th
Thor Heyerdahl history, consulting what was then the world's largest private collection of books and papers on Polynesia, owned by Bjarne Kroepelien, a wealthy wine merchant in Oslo. (This collection was later purchased by the University of Oslo Library from Kroepelien's heirs and was attached to the Kon-Tiki Museum research department.) After seven terms and consultations with experts in Berlin, a project was developed and sponsored by Heyerdahl's zoology professors, Kristine Bonnevie and Hjalmar Broch. He was to visit some isolated Pacific island groups and study how the local animals had found their way there. Just before sailing together to the Marquesas