As long as humans have been communicating, they’ve been drawing on walls. But what we think of as graffiti is probably marked by the invention of the aerosol paint can in 1949. Spray-painted graffiti became a common sight in Europe in the ’60s and is widely thought to have started in the US in Philadelphia in the ’70s, moving to New York City later that decade. The street art — or as it was more often classified at the time — vandalism, maneuvered in message from the personal to political to punk rock. By the ‘80s it started reflecting the emerging hip-hop culture. And that was where it found the artist who would one day be known as Man One.