Athens is the capital city of Greece located on the Mediterranean coast. It has a population of over 3 million people, about one-third of Greece's total population. Some of Athens' most important historical monuments include the Acropolis, home to the iconic Parthenon, as well as the Ancient Agora, Theater of Dionysus, and other sites from ancient Greek culture. Athens emerged as an important commercial center but was later defeated in the Peloponnesian War by Sparta in the 5th century BC. Today, Athens remains a center for industry, banking, tourism, and transportation in Greece's economy.