What is tourism

I've often wondered about the origins of tourism. Today I was in Utrecht, my cousin had invited me to drop by tourism convention where she was working representing the Dominican Republic. There were many countries there, some like Turkey had huge stallls. Others were a bit more conservative. I was surprised that Catalonia's booth was almost as big as the whole of Spain.
It was interesting to walk around and see each country selling some of their culture, or sights.
It also surprised me to see NYC represented as well a other parts of the US.
Here are some pictures.