Today’s richest individuals—Elon Musk, Bernard Arnault, Jeff Bezos, Larry Ellison, and Bill Gates—amass fortunes that seem astronomical, but how do they compare to the giants of yesteryears, like John D. Rockefeller? By adjusting for inflation and measuring wealth relative to the U.S. Gross National Product (GNP), we gain a clearer perspective on the scale of wealth and its sources across time.