Stunning and vibrant artwork can be found on buildings, sidewalks, street signs, and other surfaces in cities around the world. New York City is considered the birthplace of graffiti and has been a cradle for urban artists since the beginning of the 1970's. Thousands of miles away in Barcelona, the city streets are filled with an explosion of creativity. Since the graffiti laws there have been more lenient in recent years, artists from around the world have journeyed to this vibrant city to leave behind their colourful work on walls, road signs, and street furniture.