Grafitti in those hystorical monuments should be several punished with cutting hands off for example. Disappointing seeing that decadence. It is sad
Also done in trains, even I think they have some permission from some institution doing that, as it is not so easy and takes time, should be avoided in extreme law and punishment. Only in accordance with community and city some walls very specific chosen should be artistic painted, to bring life to them, not confuse graffitis.