How can a physical map help explain the historical development of a country?
Just one example : Poland
Look at a physical map of central Europe. Can you find Poland? Italy is Easy, just south of the Alps. Spain? Look for the Pyrenees. Britain? That big island just North of France. But Poland?
Poland has very modest physical definition. A vast plain between Germany, few ancient Russian provinces and the Baltic Sea. Do not get me wrong. Poland is a great nation with its own language, strong traditions and a profound culture. But Poland actually disappeared three times from the political maps as of 1772 because of powerful and arrogant neighbours and lack of physical boundaries.
Now take a counter example: Italy. Italy never was a State until 1861. Before reunification, there were at least a dozen independent kingdoms, Duchies and Republics within the Peninsula mostly fighting one another for territory since the fall of the Roman Empire.
However, no one ever doubted the existence of Italy, nor wandered where it was. Just one look at a physical map of the Mediterranean and there it was for everyone to see.