“She used to sing around here,” Charles Bergen said as we looked at the bronze sculpture of Flora Molton nestled in an old call box in front of a Macy’s store downtown. “She sang at the intersection of gospel and blues.”

We were at an intersection ourselves — 13th and G streets NW — and about to set off on an informal walking tour of eight sculptures that Bergen created inside cast-iron fire and police call boxes, infrastructural relics once used by the city’s first responders.

It was local historian Mara Cherkasky who came up with the project’s unifying principal: a celebration of next year’s centennial of the 19th Amendment, granting women the right to vote, by marking the contributions of D.C. women.

Bergen figured that Washington had many statues of metaphorical women — Liberty, Freedom, Columbia — and of such deep historical figures as Joan of Arc. “But,” he said, “there are very few actual women.”

Women such as Molton (1908-1990), a visually-impaired gospel and blues singer who came to Washington from Louisa County, Va. At first, Molton busked outdoors, the street her stage. Even after she was discovered by the District’s folk community in the 1960s and began performing at such places as the Library of Congress and Smithsonian Folklife Festival, Molton would often sit with her guitar amid the bustle of downtown and sing about salvation.

Molton was a public artist. And that’s what the 56-year-old Bergen is. You’ve probably seen stuff created in his Brentwood, Md., studio. Walked on it, even. He made the animalistic Chinese zodiac crosswalk at Seventh and H streets NW in Chinatown. His red die-cut sign at First and F streets SE shows two dinosaurs in a chase: a Capitalsaurus on the heels of a Falcarius.

Bergen has transformed other call boxes, too, including six on Rhode Island Avenue NW. One celebrates Bo Diddley, who lived and recorded in a house in the neighborhood.

Call boxes — in use from the 1890s to the 1970s — have become signature settings for Washington’s public art. The artworks inside may not be as grand as a marble Abraham Lincoln or Martin Luther King Jr., but they reward the attentive pedestrian.

“The ones that face east are best looked at early in the morning,” Bergen said.

Next to Molton’s bas-relief is a call box celebrating Alma Thomas (1891-1978), the Washington Color School artist. The base of the box is stenciled with highlights of Thomas’s life. A small plaque affixed to the box provides a more detailed biography. Each call box is a mini history lesson.

Bergen is a local, a graduate of St. Albans who went to Yale University for undergrad then returned to Yale to become an architect. He made a specialty out of overseeing construction projects.

“Construction administration is so stressful that I needed something to do on the weekends that I had control over,” he said. That was making art. One of Bergen’s earliest large-scale creations was a 12-foot-long lobster he fashioned out of copper and a severed branch from his parent’s yard.

Bergen continued to juggle architecture and art until the fall of 2013, when one of his designs was shortlisted for the Chuck Brown Memorial Park. He didn’t win that commission, but he realized that if he did, he couldn’t really be a part-time architect and a part-time sculptor. The art won out, and he quit his day job.

We walked in a ragged clockwise circle, passing call boxes honoring civil rights activist Mary Church Terrell, poet and composer Julia Ward Howe, suffragist Alice Paul, Washington Post publisher Katharine Graham and D.C. home rights activist Josephine Butler.

“There were lots of strong women in my life,” Bergen said. His mother taught history at the Washington Ballet, back when the dance company had its own school for young dancers, then at the Madeira School. An aunt started the Victorian Society in England. His wife, Sujatha, is the health campaigns director at the Natural Resources Defense Council.

The $175,000 call box project was commissioned by the Downtown BID. Artists who assisted Bergen include Darian Lassiter, Nathan Cousins, Mathew Andrews, Tsahai Pettiford, Amber Logan, Hakeem Olayinka, Aaron Rogers, Brandon Bailey, Elsabe Dixon, Colby Johnson, Sanjaya Wilson and George Tkabladze. Art students with the Marion Barry Summer Youth Employment Program were also involved.

We stopped at Vermont and K NW, next to the call box sculpture of Elizabeth Keckley, an African American seamstress and confidante of Mary Todd Lincoln.

“She’s got a great location,” Bergen said, meaning the call box is surrounded by plenty of sidewalk. “You’re not going to get hit by a car while you step back to look at it.”

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/john-kelly.