Who doesn’t love to leave their mark? Whether with words or images, we humans are obsessed with sharing our mind’s eye. Centuries before Twitter or Twitch, the ancient Greeks and Romans communicated by writing messages on bar walls. Get this: The word “graffiti” actually comes from the Greek “graphein.” Now, from American teenagers artfully tagging city walls to postmodern artists banking millions from murals, graffiti remains a form of expression without equal. But things are changing. With local governments and companies moving in on the most Insta-friendly walls and writers aching to stay true to their art, what does the future hold for these impermanent pieces? Today’s Daily Dose takes you on a fascinating journey alongside the unsung can- and brush-wielders you need to follow, introduces the places where “wall bombing” is a matter of life-and-death and shows you how to become an expert graffiti snob.