John D. Rockefeller was the richest man the world had ever seen.

But for most of his adult life he didn’t have electric lights, air conditioning, or sunglasses. And he never had penicillin, sunscreen, or Advil. This is not ancient history: One in twenty…

Do you know what’s happening in this picture? Literally one of the most important events in human history.

History is infinitely complicated. Too much stuff has happened for anyone to…