Athens is the capital and largest city of Greece; popular for being one of the oldest cities in the world with its history of almost 3400 years. The ancient city was at the foot of the Acropolis. The Port of Piraeus is part of the Greater Athens. Numerous testimonies of its glory were preserved like the Parthenon, the Agora and the Temple of Hephaestus, the Olympeion, among others. The city extends on the plain of Attica, on the shores of the Aegean Sea. Plaka is the oldest headquater and Kolonaki is the upscale neighborhood. Because of its geographical position, the city suffers pollution and there is also a lack of green space. Unfortunately, since 2009, the city lost many inhabitants because of the economic crisis.
There are Sundays when you can visit archaeological sites such as the Acropolis for free, ask the calendar where you are staying.
Wear comfortable, flat shoes like sneakers especially in archaeological sites because there are lot of marble and is quite slippery.
For a great view of the city, go to the Lycabettus Hill.
You can tour the city by public transport without problems: metro, bus, train. You have the subway that arrives at the airport too. The tram (line 4), connects Piraeus to Syntagma Square. Regarding taxis, they take several passengers who go more or less in the same direction.
If you do a multi-day stay in the city, visit the Museum of the Acropolis and the National Archaeological Museum, it is worth it!