Final answer:
Heyerdahl and von Daniken proposed unscientific theories attributing ancient civilization developments to Egyptians navigating to the New World and extraterrestrial intervention, challenging established historical explanations of human achievements.
Step-by-step explanation:
Both Thor Heyerdahl and Erich von Daniken have proposed theories concerning the development of ancient civilizations that lack substantial scientific evidence. Heyerdahl suggested that Egyptians could have navigated to the New World, while von Daniken speculated that extraterrestrial beings influenced major human accomplishments such as the construction of the pyramids. These theories share a common trait: they both challenge conventional archaeological and historical explanations about the rise and achievements of ancient civilizations by introducing alternative origins—outside human capabilities or beyond the known paths of human migration.