A lesson in ancient Greece begins when your cruise ship docks in the Port of Piraeus (pronounced pee-reh-us), which has served as the port for Athens since the fourth century B.C. As an ancient Athenian port, it was frequented as the most important trade center of the world. In fact, some of the ancient protective walls can still be found here. Its picturesque natural harbors, Zea Pasalimani and Mikrolimano, are still in use today. Today, the Port of Piraeus is one of the largest passenger ports in Europe, where 20 million passengers disembark every year. Its cruise terminals are within walking distance from the city of Piraeus (which is known for local office buildings and not much more) and the Athens metro station. Many rightly beeline for the historic center of Athens to explore the famous Acropolis and the must-see monuments of the Greek capital, such as the Temple of Olympian Zeus, the neighborhoods of Plaka and Monastiraki, the National Archaeological Museum and the Acropolis Museum. Athens city proper is 8 miles to the northeast and is easily accessible via a 30-minute metro ride or a 20- to 30-minute taxi ride, depending on traffic. If Athens isn't the destination in mind, the Greek islands are. The port is also a major departure point for ferries to outlying islands.