When you duck under the Metra tracks at 47th Street you do it through an underpass whose walls gleam with fresh white paint. But it’s not supposed to be that way, says Sam Mulberry, who helped paint murals on those walls in the mid-90s. A few weeks ago, the city painted over them without explanation.

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He asked a neighborhood graffiti artist he idolized named Wyatt Mitchell–best known as Attica, though he’s used half a dozen other monikers–to bring some people over to teach him how to paint. Among the people Mitchell brought to the wall was Mario Gonzalez, one of the founders of Higher Gliffs, then a loosely organized street-youth collective that advocated self-expression through public art (it’s now better organized as a nonprofit, though its goals remain the same).

The 47th Street underpass is divided into 11 walls on the south side and 12 on the north, and all of them were covered with aerosol and brush murals. The north side was dedicated to a project called “The Twelve Doorways of Perception,” a “group prayer,” says Mulberry, that depicted “12 different views of spirituality,” including elements of Latin-American, African, Mayan, Indian, and Native American spiritual practices. The south side was the “Gallery of Style,” an annually changing wall of fame featuring local and international graffiti legends. One section became a memorial two years ago when Mitchell died. “You don’t paint over memorials,” says Mulberry. “What [the city] did was doubly disrespectful.”

Some relatively new graffiti-style murals are alive and well on the walls inside Humboldt Park’s Reversible Eye Gallery. A few weeks ago the gallery invited street artists, graffiti writers, art school kids, and friends to paint whatever they wanted as part of Public Image Enemy, a bimonthly series of visual and performance art, dance, and music shows running until the end of November that’s meant to connect the common points between hip-hop and punk rock.