N is for Neanderthal.
Neanderthals dominated Europe for tens of thousands of years. Then, about 60,000 years ago, when humans emerged from Africa, the Neanderthals began to die out, which scientists find mysterious. (Hint: It has to do with humans emerging from Africa.)
Although there are traces of Neanderthal DNA among humans, the Neanderthal was not our ancestor but a whole nother species. It would be nice to believe that humans overwhelmed them with superior brainpower, but the reality is we probably just had a much faster reproduction rate. We weren't smarter, just hornier.
Contrary to what you might think, Neanderthals weren't hairy creatures that walked bent over and grunted at each other. They stood upright, had a language, and used tools. If you saw a Neanderthal walking by dressed in modern clothes, you would not notice anything particularly strange.
Neanderthals cared for their sick and buried their dead. On the other hand, at least one scientist says they raped and killed humans and weren't above eating human flesh. So all in all, they weren't all that different from us.