Sub cultures

Often the best and easiest way to get around a new city is to take the underground, metro or subway. Not only do you save money but you get a fantastic glimpse into daily life. Many cities around the world have invested not only money into new snazzy trains but also into the architecture and art in the stations.
Here is an article in business week which highlights twelve of the best.

Also urbanrail.net is a fantastic source of underground maps from cities around the world

Street Art in Buenos Aires

Not that anyone needs another excuse to visit Buenos Aires but here it is anyway.
Since the economic crash back in 2001, many street artists have emerged, most with a strong background in graphic design. Tours are now being offered by graffitimundo for AR$75 pesos. You'll tour the graffiti scenes and learn all about the history and artists involved.