How the Hell Were the Neanderthals, Right?

The seafaring folks somehow were able to make pretty accurate maps during the Ice Age and beyond. Who the hell were they? How did they figure it out? How advanced was that shit? I just think it's awesome that someone is out there like really asking those questions instead of just being like, "Oh, you know, that was that map was a guess" And then another thing they got into was like different human species. So people have come on and they talked about how we interbred with the Neanderthals,. So I guess they were the same species as us because you can't breed with a different species, right? The same species were the actually different ones that weren't