A high-end bridal shop, a psychotherapy practice and a public relations firm are housed in the elegant towers of Hampden Castle.

But lurking in the basement is a grim remnant of another era: a duo of dark, damp, isolated cells.

The walls of the cell are lined with brick and coated with white dust. The only source of fresh air is a small slatted opening. The inside of the metal doors are punched, as if they have been beaten by thousands of fists.

They probably were.

The building, the old Northern District police station, was built in 1899 when Hampden was a rural village, home to the farmers and mill workers that dotted the banks of Jones Falls.

Despite the humble surroundings, architect Henry Brauns he designed a majestic building with gables, turrets, stained glass windows and glittering gargoyles. Not surprisingly, the Castle, as it’s called, won a spot on National Register of Historic Places in 2001, during which time the station was closed and the building was sold to a private developer.

There is a police gym, a prison matron’s suite and 16 prison cells, described as “steel cages” in an 1898 article in the Baltimore Sun. The rear of the complex included a shooting range and stables for the horses that pulled the police wagons.

Baltimore being Baltimore, bizarre things started happening almost as soon as they opened. A Frenchman named John Pensoe and his pet grizzly bear were locked up together after breaking into a vacant house in Woodberry, according to a newspaper that historian Johns Hopkins shared in a video about the Castle.

Then, in 1935, a dozen members of a glee club spent the evening harmonizing in their cells after being arrested for disturbing the peace at a Falls Road gathering place called The Hollow.

But this is not an episode of “The Andy Griffith Show.”

Police in the early 1900s were often brutal and dehumanizing, he said Michael Casiano, professor of American studies at the University of Maryland, Baltimore County.

“The police didn’t worry about the comfort of the prisoners,” Casiano said, noting that inmates in the city jail were kept in a stuffy space adjacent to the boiler room.

And the underpowered — people of color, poor people, immigrants and the mentally ill — were often locked up for mundane reasons, said Casiano, the author of a forthcoming book on Baltimore police from the end of the Civil War to the 1930s.

People arrested for minor offenses had to pay a fine to be released, which went into a discretionary fund controlled by the officers in charge of the post, Casiano said, adding an additional incentive to make arrests without discrimination. Those charged with more serious crimes were eventually transferred to the city’s main jail downtown.

Police at local stations were known for getting people to confess to crimes they didn’t commit, Casiano said. They “sweat” the prisoners, subjecting them to hours of grilling by high-ranking officials. They deprived the prisoners of sleep, posting officers to rouse them whenever they dozed off. And it would force prisoners into solitary confinement.

Which brings us to those basement cells.

In the early and mid-1800s, there was a belief in the rehabilitative power of isolation, Casiano said. Law enforcement believed that a Bible and quiet reflection could help criminals change their ways.

But until the old North District station opened, its use was “purely punitive,” Casiano said.

“Publicly, it was represented as a way to protect the public from an extremely dangerous presence,” he said. “But solitary confinement has a way of destroying the spirit of someone accused of a crime.”

It’s easy to see how spending time in brick cells can destroy your spirit. The space is so narrow that you can’t extend your arms without touching the walls. There is no bench or bed. Just a dusty floor to walk on and a few spiders darting into the cracks.

Famed Baltimore filmmaker John Waters spent a few hours behind bars in the Northern District, but not in solitary confinement.

It was November 1968, and Waters, then 22, and a few collaborators were shooting a scene for the movie “Mondo Trasho” on the nearby campus of Johns Hopkins University. Waters and others were arrested because an actor was nude. Somehow, actor Divine, Waters’ dear friend and muse, managed to escape despite driving a red convertible upside down while in full drag.

The case attracted national attention, and the ACLU stepped in to represent Waters. When Judge Solomon Liss dismissed the charges the following February, he spoke in verse:

“And so – go now and sin no more.

Undress, if necessary, but behind the door;

And if again, you listened to the call of art,

Rest assured that the judge will do his part.”

Waters said he didn’t remember much about the cells in the old Northern District, other than they were “old school” and his friend David Lochary gave him a pack of gum folded into a fan through the metal bars.

But the small courtroom in the old Northern District station captured Waters’ imagination. He filmed a courtroom scene for 1990’s Cry-Baby there, with heiress Patty Hearst playing the mother of a juvenile delinquent.

Waters, who lives nearby, often stops by the Castle.

“I always think about it when I drive by,” he said.