The Graffiti is a very controversial type of Art, in Italy lately there is a debate if and how let Graffiti artists to express themselves legally. In big and small towns city halls are trying to find a way to authorize part of their territories to make Graffitis.
There are some of them I really like (but few..), in London recently there has been one sold for a lot of money because this phenomenon is becoming something to use and promote to make money.
here a good axample from Miami: the murals “Art on the walls”.
Photo and info Via: thecoolhunter