Geography is important because of how it impacts people and culture. People have the innate ability to adapt to their environment. As a result, cultures develop around the presentation of the land. Modern societies that have had mountains or other barriers preventing contact with each other tend to be multicultural in nature. They may have a multitude of languages or religious practices within a small geographical area. This is because the different cities or villages evolved independently of one another.
Cultures that have access to waterways tend to have stronger economic and commercial structures. This is due to the fact that they have utilized the waterways to benefit trade and transportation with the rest of the world. This was witnessed in the ancient world but still exists today. If you look at landlocked regions of the world and how economically disadvantaged they are, you recognize the significance of having access to the seas.
The effect of mountains and water on cultures and economic development are just two examples. Geography and climate play a very significant role in how people live and behave. This was as true thousands of years ago as it is today.