With a gross metropolitan product (GMP) of $737.9 billion, the LA metro's economy is bigger than Turkey's ($732.2) and slightly smaller than the Netherlands' ($782.3) -- the equivalent of the 18th largest nation in the world.
If your city isn't listed, where do you think it might fit in?
http://m.theatlantic.com/business/archive/2011/07/if-us-cities-were-countries-how-would-they-rank/241977#slide8