One of the fascinating aspects of Barcelona otherwise clean and proper street life is the ubiquitous graffiti on the buildings lining the sidewalks. As opposed to US graffiti, which seems random and destructive, here it has more of a "street art" appearance, with vibrant designs and messages. The graffiti in Barcelona is especially striking whenever the shops are closed: the lowered metal gates are covered in colorful markings, pictures, and designs, which frequently related to whatever is being sold behind them. During siestas and weekends, this street art forms a striking backdrop to the everyday activities that take place on the sidewalk, which makes for some pretty cool pictures.
Last Sunday, I walked around the Raval, taking pictures of some of the more interesting designs. You can find many of them here, but I've also attached a couple of shots below.