It's estimated the Amazon contains about 100 tribes never contacted by outside civilization. And there are hundreds more uncontacted people in jungles all over the world. They've probably never heard of the black plague, or the Dark Ages, or the Mongol hordes, or World War II, or Donald Trump ... and we've never heard of all the calamities they've survived, either.
Lemont, what's the one thing you'd change if you could go back in time. Kill Hitler. Something personal, I mean. Like maybe missed opportunity. I guess I'd have prevented the dark ages. That way we'd be 1,000 years more advance right now. How's that "personal"? I'd get to avoid your question from my roof on Neptune.