One thing I learned from the outside, the US - like any large country, BTW - is wildly diverse in pretty much every aspect.

It's almost intuitive if you consider the distance from Bangor to LA is pretty much the same distance as Madrid to Moscow. Think of the diversity between Madrid and Moscow. Bangor to LA won't take you through an equal amount of diverse cultures, the US is a single country after all, but the diversity is certainly there.

Not that intuitive, as the country has a language in common and one can simply drive from Bangor to LA without any local government asking questions. I have the impression cultural differences spring more from the economic and educational ones, unlike Madrid and Moscow, which have very long histories that are almost completely disconnected for most of that time.