In which year did Norwegian explorer Thor Heyerdahl sail to North America in a papyrus boat?

Thor Heyerdahl, a renowned Norwegian explorer, completed his famous voyage across the Atlantic Ocean on a papyrus boat named Ra II in 1970. This expedition was part of Heyerdahl's research into ancient maritime navigation and the possibility of pre-Columbian trans-oceanic contact. He set out from Morocco, aiming to demonstrate that it was possible for ancient peoples to have traveled from Africa to the Americas using simple, traditional vessels. The journey significantly contributed to the discussions around ancient civilizations and their capabilities. The year 1970 marks an important moment in exploration and the study of historical maritime routes, making it the correct answer.