It was merely a few decades ago that most ancient history books taught the theory that the first humans to occupy North American crossed a land bridge from Siberia to what is now Alaska, then migrated southward along the Pacific coast, continuing to Central America and South America. That simple explanation was supported by findings of evidence of what became known as the Clovis culture and that group became the accepted ‘first humans’ of the Americas. That theory began to be doubted as pre-Clovis evidence was found in North America, while signs of a completely different group of people began to appear in South America – people who traveled there via boats across the Pacific. That theory turned in a surprising new direction recently as researchers using DNA from two ancient human individuals unearthed in two different archaeological sites in northeast Brazil found the presence of DNA from Neanderthals and Denisovans. Even more surprising, they also uncovered the first evidence of a south-to-north migration up the Atlantic coast of South America. Does this change everything?