US cities...and their national roles

All US cities contribute to the good of the US in a variety of ways. But some cities provide a special service to the nation in one or more ways. I'm talking about cities with a special role in the US, fields they so dominate that no other city comes close. I'll include some examples I can think of and hope that others will contribute ones of their own: New York: finanace Washington: government Chicago: internal transportation Los Angeles: motion pictures Nashville: country music Miami: the link between the US and Latin America Detroit: cars (weakening) Houston: oil Vegas: sin (what happens here stays here) Orlando: theme parks>