With 9 hours to spare, you’ll have enough time to travel into Athens and see some of the sights before heading to Piraeus to join your cruise. Athens airport is around 20 miles from the city itself and there is an express bus service which should get you there in a round half an hour. The journey from Athens to Piraeus is short too, so allow around 20 minutes for this. Once in Athens, be aware that it’s a very busy city and crowded, so allow extra time to get around. The main must-see in the city is the world-famous Acropolis, which is home to a number of fascinating ancient ruins such as Parthenon, Erechtheion and Hephaistion. The Acropolis museum at the foot of the hill where the ruins lie is certainly worth a look too. If this isn’t for you, or you find yourself with extra time to spare in the city, the Tomb of the Unknown Soldier and the Old Olympic Stadium are popular landmarks, while the flea market neighbourhood of Monastiraki will offer you an authentic taste of the city and is a great place to pick up a bargain or soak up the atmosphere of a Greek taverna.