The corner of Houston Street and the Bowery has been home to murals by some of the world’s most renowned street artists, from Keith Haring to Os Gêmeos to JR. The latest titan of street art to take over the giant canvas? Banksy.

The anonymous British artist’s 70-foot-long mural was unveiled on Thursday, and it protests the imprisonment of the Turkish-Kurdish artist and journalist Zehra Dogan, who was sentenced last March for painting the destruction of a predominantly Kurdish town, with Turkey’s flag flying over rubble.

“I really feel for her. I’ve painted things much more worthy of a custodial sentence,” Banksy said in a statement to the New York Times.

Banksy’s sparse mural mostly consists of black hash marks, which visually represent jail cell bars and count the number of days that Ms. Dogan has spent in prison. (A similar array of hash marks also recently appeared in another protest art piece — “Parkland 17,” which counts the number of Americans killed by guns daily.) A rendering of Ms. Dogan herself peers out of one of the cells, with her left hand gripping a bar that doubles as a pencil. “Free Zehra Dogan” is written in the bottom right corner. She still has 18 months left to serve, and remains unaware of the mural, according to a news release.