Piraeus is a port city in the region of Attica, Greece. Piraeus is located within the Athens urban area, 12 kilometres (7 miles) southwest from its city center (municipality of Athens), and lies along the east coast of the Saronic Gulf.
According to the 2011 census, Piraeus had a population of 163,688 people within its administrative limits, making it the fourth largest municipality in Greece and the second largest within the urban area of the Greek capital, following the municipality of Athens. The municipality of Piraeus and several other suburban municipalities within the regional unit of Piraeus form the greater Piraeus area, with a total population of 448,997.
Piraeus has a long recorded history, dating to ancient Greece. The city was largely developed in the early 5th century BC, when it was selected to serve as the port city of classical Athens and was transformed into a prototype harbour, concentrating all the import and transit trade of Athens. During the Golden Age of Athens the Long Walls were constructed to connect Athens with Piraeus. Consequently, it became the chief harbour of ancient Greece, but declined gradually after the 4th century AD, growing once more in the 19th century, especially after Athens' declaration as the capital of Greece. In the modern era, Piraeus is a large city, bustling with activity and an integral part of Athens, acting as home to the country's biggest harbour and bearing all the characteristics of a huge marine and commercial-industrial centre.
The port of Piraeus is the chief port in Greece, the largest passenger port in Europe and the second largest in the world, servicing about 20 million passengers annually. With a throughput of 1.4 million TEUs, Piraeus is placed among the top ten ports in container traffic in Europe and the top container port in the Eastern Mediterranean. The city hosted events in both the 1896 and 2004 Summer Olympics held in Athens. The University of Piraeus is one of the largest universities in Greece.