London. Berlin. Paris. New York. These are the cities oft ballyhooed for their vibrant walls and eclectic outdoor art. They are the major cultural hubs that attract stars like Banksy and Shepard Fairey and JR, artists who happily spray, paste and paint their ways across the towns. Add in Mexico City, Prague, Montreal and a few other familiar capitals and you’ve got yourself a list of the best street art cities to visit.