Culture is not determined by geography, but geography may shape it, and the opposite is also quite true. People are kept separate by distance. Of course, this isolation also allows for the manifestation of extreme distinctions, such as in gene pools, languages, and faiths. We can travel to just about any gathering of people in a day, yet we normally choose to stay in our own country. Cultural reinforcement through generations is effective and is here to stay. Furthermore, even the peripatetic types retain their culture. Culture is hybridized, imported, and exported. From a very young age, we can easily distinguish unfamiliar habits from those of our society. Nation states are the result of putting steroids into the us-them dichotomy. Thus, culture determines geography, the crucible in which different cultures developed. On a political map of the world, you can see this every day.