When you paint on a wall in the middle of the city, people want to talk to you.

They want to tell you how they would have painted things differently, choosing a different shade of green or a different subject entirely. They want to know why you're there. They want to tell you their stories.

"You did that, man?" they ask. "That is all right."

For six days last month, the artist known as Gaia painted on the side of a Korean rice cake factory in the 2000 block of N. Charles St. in Station North.

First the Roman god Mercury emerged on the gray cinder-block wall, gazing west toward a beauty supply store. Then a tiger took shape over the trash-strewn vacant lot. A glowing landscape appeared, then an image of the University of Baltimore's new law school. The face of an arabber, a friend of Gaia's, materialized on the eastern edge, his eyes shaded by the brim of an Orioles cap, lips parted as if about to speak.

"I just sit here all day and receive stories," said Gaia, 25, an internationally acclaimed street artist with a wild mop of brown curls. "You are given a tremendous power when you're painting on a wall."

Korean grandmothers, Latino construction workers, men in traditional Muslim dress, a dancer at the Hustler Club, commuters from Penn Station and many residents of a nearby high-rise for the elderly and disabled paused as they passed the wall.

Gaia's mural kicks off Open Walls Baltimore 2, a series of at least 17 works that will appear on walls throughout Station North and nearby blocks over the next 21/2 months. The project has sparked conversations about art — and a dispute over inclusion as well.

Gaia, a 2011 Maryland Institute College of Art graduate whose legal name is Andrew Pisacane, is curating the series, as he did the first Open Walls project in 2012. About half the artists this time are people with Baltimore roots, including the prolific muralist Ernest Shaw; many of the others are friends and associates Gaia met while painting in Europe, South Africa and Argentina.

The project is organized by the Station North Arts and Entertainment District, with major funding from the National Endowment for the Arts, the PNC Foundation and the European Union National Institutes for Culture.

Ben Stone, the district's executive director, said that people clamored for a second round of murals after the first Open Walls project. The 22 murals from the first series add to the distinct character of the neighborhood, which is home to theaters, galleries, restaurants and studios.

"I'd much rather pay someone to do a mural than put a big Station North sign out," said Stone. "We use it as a hook to get people to come in."

But the second Open Walls project has met with some criticism. Members of the activist group Luminous Intervention projected a short film on the wall outside of the Metro Gallery at the program's kickoff party to call attention to what they saw as an underrepresentation of female artists in the mural project. The film pointed out that 14 of original 15 murals were slated to be painted by male artists.

Olivia Robinson, a MICA professor and member of Luminous Intervention, said she was struck by how many passersby commented that they hadn't realized that the group of artists was overwhelmingly male until they saw the projected messages.

"If the entire roster were 92 percent women, my guess is that is something people would really comment on," she said. "But when it's 92 percent men, people don't notice. It's what they expect."

Stone said Gaia chose artists who were interested in coming to Baltimore to work in Station North but failed to include enough women artists. Stone said his organization was negotiating with other artists and, as of Monday, had confirmed the participation of two additional female muralists: Betsy Casañas of Philadelphia and Tatyana Fazlalizadeh, of Brooklyn, N.Y., who created a striking series of images of women known as the Stop Telling Women to Smile project.

Baltimore has sponsored mural programs since the 1960s and more than 170 have been painted on city walls in the past 27 years. It's only recently that the city has emerged as an important hub for street art.

Most of the city's mural projects have historically been "community-driven," said Bill Gilmore, executive director of the Baltimore Office of Promotion & the Arts. Neighborhood leaders would choose an artist, theme and wall, and approach BOPA for funding, he said. BOPA recently decided to fold the mural program into a "transformative" art project, allowing for more ambitious and complex projects, Gilmore said.

Wilfried Eckstein, a member of the European Union National Institutes for Culture, said his group generally focuses on Washington but was intrigued by Baltimore's arts scene. Many European nations are also dealing with the post-industrial challenges that Baltimore faces, he said.

In addition to the mural project, the European cultural group is helping to fund a series of artworks at Baltimore transit hubs. They'll be sponsoring three parkour performers at Penn Station later this month in conjunction with Open Walls.