Athens is the capital city of Greece and the most important financial, industrial, maritime, political and cultural center of the country. It is one of the most famous cities in the world. It is also one of the world's oldest cities. Scholars disagree on whether the city is named for the goddess Athena, or the goddess for the city. Athens has a population of about 4 million people and is growing. It is in the prefecture, or division of the country, of Attica. Its port, Piraeus, is both the largest passenger port in Europe, and the second largest port in the world. Athens has a borderline cold semi-arid climate ("BSk" in the Köppen climate classification) and a hot-summer Mediterranean climate ("Csa" in the Köppen climate classification). The average rainfall is relatively low, due to the rain shadow from the Parnitha mountains. Frost is infrequent and snow does not occur every winter.