Guns, Germs, and Steel: The Fates of Human Societies, published in 1997, talks about societal changes in terms of geographical influence. Religion, being a very important aspect of society (if no the most important), also seems to be influenced by factors other than simple faith and revelation. Indeed, the New Atheism movement is powered by the belief that religion is fundamentally irrational (click here for a brief outline of their mission/vision).
The author of my current article, however, questions the validity of such argument, namely, "religion is irrational because it does not always confirm to natural laws". The author argues that, while there may be many reasons why religion can be irrational (e.g., it doesn't confirm to natural laws; it is influenced by external factors such as geography; it is more emotionally comforting than anything else), they fall short as sufficient conditions for such conclusion.