The walls of Athens are covered with graffiti as Barcelona or Berlin, the graffiti are everywhere present and express dreams, despair and passions of the population.
You will certainly learn more about the current situation in Greece by looking at the walls than in any newspapers.
Most of these pictures were taken in the area of Metaxourgio.
Website of some street artists in Greece:
Bleeps.Gr: http://bleeps.gr/main/
Sonke: www.sonke.gr
Dimitri taxis: www.fatcap.com/artist/dimitri-taxis.html
Alexandro Vasmoulakis: www.vasmou.com
Greg Papagrigoriou: on Flickr
And mine: www.romain-chauvet.com