San Pedro de Atacama, Chile: population: about 11,000.
The town is supported by tourism and that is very obvious when you visit. I heard people talking in many languages, and it appears most are in their late 20s or 30s. I spoke to one, a man from Ireland, and he said he's met at least five people from the US on his journey. I realized today that my journey of South America starting in Colombia and going south is the opposite of what most people are doing. And there's this - everyone I have met and talked to in the past 4 months has been heading north. I have yet to meet anyone else going south. Anyway, San Pedro is very small, something like 12,000 people. There is one supermarket, and one or two gas stations out on the highway. But, there are many, many, many shops catering to tourists.