In high school I learned about Greek city states. City states, except for possibly Singapore, are a feature from the past. Yet, trade between the world's thousands of cities is incredibly important today. Trade between cities may even be more important today than it was back then to those ancient Greeks.
I had these thoughts as I sat down to lunch with my wife and her childhood friend. Our meal was only possible thanks to trade between distant cities.Cauliflower from California, cheese from France and from Italy. So much of my lunch was not produced in London, nor in Ontario, nor in any part of Canada.
As a teen I worked in plastic factories making car parts. I recall that one plastic injection machine I used was designed in and built in Italy. When my day making plastic steering wheels was done, I'd get in my Swedish car, the parts made in Europe but assembled in Halifax, Nova Scotia, and I'd drive home.