Greece is a rocky country with a mountainous interior, poor soil, and few natural resources. It includes a large archipelago containing many small islands and a few large ones, the largest of which is Crete, where the Minoan civilization preceded that of the mainland.

Perhaps the principal effect of this geography on all aspects of Greek culture was that it made Greece very difficult to unify. Most Ancient Greeks would not have understood where you were talking about if you mentioned Greece (the words "Hellas" and "Hellenes" are comparatively rare in Greek literature), since they thought of themselves as Athenians, Spartans, Corinthians, or members of whichever city state they inhabited.

The city states, cut off from each other on land by rocky mountains, developed chiefly as maritime powers and traders. Like the Phoenicians, all the Greeks lived near the sea. They did not have very much to trade, however, since little but olives would grow in Greece, and so they never grew very rich. Perhaps surprisingly, this lack of great wealth, in comparison with such neighbors as Lydia and Persia, had two very positive effects on Greek society. For centuries, they lived side-by-side with large empires but were never conquered, mainly because their neighbors did not think it worthwhile to go to war for so small a prize. It was only the support of Athens and Eretria for the Ionian revolt that brought the Persians to Greece at all.

The other effect of Greece's relative poverty was that Athens in particular concentrated in excelling in cultural and intellectual wealth. Lord Clark points out in Civilization that, while excess wealth is necessary for art to flourish, extremes of wealth do not ever seem to have been successful in producing the finest works. Lydia was famous for wealth, but we have no great Lydian drama or philosophy. The Athenians had enough wealth for cultivated leisure but not enough to emulate the vast ostentatious display of Croesus, still a byword for riches, but with no lasting achievement to show for his reign.

How did the geography of Greece play a role in their political structure?

The geography of Greece played a very important role in Greece's ancient political structure. Greece is a very mountainous peninsula. The mountains were very difficult to travel so it acted to separate pockets of people in different areas. The end result of the isolated populations was that the various areas developed independently of one another. This is known as regionalism. As the populations slowly grew, city-states developed that were autonomous of one another. This was very different than how Egypt developed many centuries earlier.

Another consequence of the barren geography of much of Greece is that farming was difficult. This meant that populations remained relatively small. Representative governments grew in many city-states that otherwise may not have been possible in largely populated states. Athens was able to develop a direct democracy, which would have been very difficult if it had a similar population as Rome.