Piraeus is one of the largest cities in Greece and is a municipality within Athens urban area. The city is located just 6 miles (12 km) to the southern of Athens city centre, only a quick metro ride of about 20-25 minutes to the Syntag,a square. Piraeus is one of the most important & ancient commercial-cum-leading port in the Mediterranean and offers many things to explore as well as take a ferry for a short cruise to the islands.
For tips about transportation from and to Piraeus, especially connection to Athens and the airport, please click here.
For tips about things major attraction worthwhile exploring please click here and here.