Is Geography Destiny? Really?

From the several studies related to history the one I find more interesting is geography. 1 week ago I had my first history class of the semester and Mr. Harris gave us an introduction of what we are going to see this year. I remember something that he said "geography is destiny". When I first heart that I was really confused. How could geography be destiny? Then he explained why he thinks that and his explanation convinced me but I was still really curious, so I felt like I had to look for something on internet. Now after the search I totally agree with Mr. Harris. In Mexico you can see a big difference between the north part and the south part. The north part of mexico share borders with united states so at the same time they share trading and manufacturing. Because of this the north part has more money and many people wants to live there, with this, making a lot of inner commercial. The south part has less population and less job opportunity because a lot of people move to the north part. The south part needs money while the north part has a high economy. The south part wants the north part to buy their products and they have to sell them very cheap. From this you can see how north have economic development very high only because is sharing borders with U.S. This means that geography is totally destiny. I think studying geography this year, already knowing this, will not be fun, but it will be interesting and interesting is more than fun!