When I was a kid and for the longest time there was only one: Howard Hughes.
Howard was a billionaire. But not the first.
John D. Rockefeller was.
Same Here!, and he lived at 10539 Bellagio in Bel Air, and when he went into incognito mode and was hiding from the world, he lived in the Hathaway Building at Van Nuys Airport, Sherman Way and Hart st. My brother lived across the street