While similar in some ways, Athens and Sparta had some key differences between them. A key difference lay in their ambitions, with Athens seeking to expand and Sparta being content with what it had.
Though Athens and Sparta were located in the same country of Greece, the two were far enough apart to exhibit slightly different climates. Athens, located in the Attica region, had a Mediterranean climate with adequate amounts of precipitation. Sparta, on the other hand, was located in the Laconia region and exhibited a more temperate and dry climate. This led to water being in short supply in Sparta.
The people of Athens (considered very modern in their outlook) encouraged a good education, especially in the arts and science. Sparta was a more militaristic society that concentrated on discipline and military service. This was exhibited in the way the people of Sparta lived, where males were expected to receive military training starting at a young age. In addition, the cultures treated their women much differently, with Spartan women prohibited from wearing makeup or jewelry, and expected to keep themselves in top physical condition. Athenian women were judged more on their beauty than their physical prowess, though exercise among the women of Athens was not unheard of.
While similar in that both cities utilized an assembly elected by the people, the two cultures also had some key differences in the form of governments they used. Athens used a form of limited democracy, where members of society served as leaders of the people. In addition, the people of Athens elected generals to lead the military. Sparta was led by an oligarchy, with two kings that gained their position by birth, with fathers passing down their crowns to their sons. The people also elected five ephors on an annual basis, as well as a senate. The kings of Sparta were not all powerful, and could be overruled by the ephors.
Militarily, the two cities were on completely different paths. Athens viewed itself as a regional power, and it had the ambitions to match. The efforts by Athens to gain control of its surrounding neighbors led to the Peloponnesian War. Oddly enough, it was the Spartans, who tended to keep to their own lands and had no ambitions for conquest, that eventually put a stop to the attempt by Athens to control the region. The Spartans' simple but militaristic lifestyle served them well in this capacity. Unlike many conquerors that would have destroyed Athens for its ambitions, Sparta was content to let Athens live on, under the condition that Athens never tried to conquer its neighbors again.
While the Spartans had no militaristic intentions of conquest, they did lend military aid to their neighbors when needed, and were viewed as some of the greatest warriors in the region. The Athenian navy was considered more powerful than Sparta's, though this did them little good on land. A majority of battles during the Peloponnesian War took place on land, and this was an area where Sparta outperformed all others.