Geography, obviously. Just read Jared Diamond. While individuals playimportant roles, geography is the route of everything and the driving force behind history. If Eintsein, Napoleon, Julius Caeser, Hitler, and numerous others had been born in the middle of the Congo instead of in Europe, than the world would still be very similar to what it is today, it just would have taken a slightly different course. There have been instances, however, where individual people and indiviual instances have shaped history. What if the early Russians had adopted Judaism from the Khazars instead of Eastern Orthodoxy (there was one king who decided this, but I can't remember the guy's name)? What if Genghis Khan had never been born? What if Jesus wasn't crucified? What if Mohammed was never born? All of these things are examples of when individual people or instances have a major impact on history, but in the overall story, geography has always been the major player. In the future, however, geography will be less important as the world becomes more integrate, but its effects will still be felt until the end of time.
