Graffiti artists have been leaving their mark on the urban landscape going back as far as the Egyptian pyramids.
Graffiti poses a modern challenge too. In Germany, the cost of cleaning up graffiti along the nation's railroad tracks runs about 10 million dollars a year according to Germany's Deutche Bahn.
Deutche Bahn reports 14,000 incidents of graffiti last year along its tracks, bridges and railway stations.
Deutche Bahn says it's not going to take it anymore. It announced it will deploy anti-graffiti surveillance in the form of mini-helicopter drones to keep an eye out for vandals.
Kimo Quaintance who teaches International Relations at the University of the German Armed Forces in Munich says drone surveillance technology makes many Germans nervous. "There's a lot of worry about drones (in Germany), mostly because people (Germans) have an intuitive sense that these capabilties are in their very early stages and we don't know where they're going to go. We don't know what kinds of power are going to be in the hands of the state or in the hands of individuals. As one economist put it: 'capabilities tend to foster policies that employ them' and so I think there's this general worry that as soon as you give this type of technological capability to the state, the original intent they had designed it for may change, as they start to use it, and it starts to grow."