Denmark doesn't have hills. It might have "hills", but not real ones. The same goes for the inhabited parts of Sweden.
Colombia could have been a better example, they have real mountains and people over there do use bicycles to do their thing. Granted, not a great percentage of the population does it because you do need to be really fit in order to handle 10% slopes, but of those that do you might get future Tour de France winners.
Yeah, I was thinking at Bernal when writing my comment. As far as I know he used to bike to school when he was a kid, and he wasn't living in the flat areas of Colombia.
