City of Athens

Athens is the capital and largest city of Greece and has a population close to 5 million people.
It is full of museums and archeological sites, with a recorded history that spans at least 3.000 years.

Modern Athens is central to economic, financial, industrial, political and cultural life in Greece, but also a popular touristic destination.

More information about Athens can be found in the following links:

The City of Athens Official Guide http://www.thisisathens.org
Attica Guide http://visitgreece.gr/en/downloads/guides
MAPS of Athens http://visitgreece.gr/en/downloads/maps

Transportation

Bus service

You can find bus stops in practically all main streets in Athens. The bus schedule is not exactly punctual but luckily there are displays in most of the stops showing when a specific bus is to be expected. There is also this website which provides real time information about the bus, bus stops and lines.

You can also find an app called "OASA Telematics App" for all three kinds of mobile OSs which provides the same real time information and comes very handy when it comes to planning your bus ride. Unfortunately, given that it is a new app and more popular than expected, it's availability guarantees are mediocre...

Subway/Train

The subway/train service, although limited in size, is a very high-quality and reliable way to move around in Athens. Note that the airport is serviced by the surban rail which connects to the subway rail that is why the fare is different. There are even trains that operate on both rails so you don't have to change train. Here's a very detailed guide for the subway and transport in Athens in general.

Tickets for the bus and the train

You can purchase tickets for the bus from the nearby kiosks or in the subway stations. A ticket costs 1.40 euros and once it is "punched" in the machines found inside the bus or in the train stations, remains valid for 90' for all types of transports with some exceptions, like the airport line (see a detailed guide here).

Taxi

You can stop a taxi by waiving your hand to the driver wherever you see one (as long as there is no other passenger in). There are also specific points where the taxis wait for passengers (called "taxi piazzas"). And finally you can always call for a taxi. You can find more details here. Note the reference to a mobile app called "Taxibeat". This is a very convenient way to find a taxi cab and then monitor the ride and the fair. Once you're in the taxi, you can use the cab's wifi internet connection (the app provides data for that once it detects it).