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

But lurking in the basement is a grim remnant of another era: a duo of dark, dank solitary-confinement cells.

The cell walls are lined with brick and furred with white dust. The only source of fresh air is a small slatted opening. The insides of the metal doors are pocked with dents, as if they had been beaten by thousands of fists.

They likely were.

The building, the old Northern District Police Station, was constructed in 1899, when Hampden was a rural village, home to farmers and workers at the mills dotting the banks of the Jones Falls.

Despite the humble surroundings, architect Henry Brauns designed a majestic building with gables, turrets, stained-glass windows and leering gargoyles. Not surprisingly, The Castle, as it is called, earned a spot on the National Register of Historic Places in 2001, around the time the station was closed and the building was sold to a private developer.

There are a gymnasium for police to exercise, an apartment for the jail matron and 16 jail cells, described as “steel cages” in an 1898 Baltimore Sun article. The back of the complex included a shooting range and stables for the horses that pulled police wagons.

Baltimore being Baltimore, bizarre things began happening almost as soon as it opened. A Frenchman named John Pensoe and his pet grizzly bear were locked up together after they broke into a vacant home in Woodberry, according to a newspaper account 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 the cells after they were arrested for disturbing the peace at a Falls Road gathering spot called The Hollow.

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

Policing in the early 1900s was often brutal and dehumanizing, said Michael Casiano, an American studies professor at the University of Maryland, Baltimore County.

“Police were not worried about the comfort of prisoners,” said Casiano, noting that overflow inmates at the city jail were kept in a sweltering space abutting the boiler room.

And those with little power — Black people, poor people, immigrants and those with mental illness — were often locked up for trivial reasons, said Casiano, the author of a forthcoming book about policing in Baltimore from the end of the Civil War until 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 station, Casiano said, adding further incentive for indiscriminate arrests. Those accused of more serious crimes were eventually transferred to the main city jail downtown.

Police at local station houses were notorious for persuading people to confess to crimes they hadn’t committed, Casiano said. They would “sweat” prisoners, subjecting them to hours of grilling from high-ranking officials. They deprived prisoners of sleep, posting officers to prod them awake each time they dozed off. And they would force prisoners into solitary confinement.

Which brings us to those cells in the basement.

In the early and mid-1800s, there was a belief in the rehabilitative power of solitary confinement, Casiano said. Law enforcement types thought a Bible and some quiet reflection could help criminals change their ways.

But by the time the old Northern District station opened, its use was “purely punitive,” Casiano said.

“Publicly, it was represented as a way of protecting the public against 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 the brick cells could destroy your spirit. The space is so narrow you cannot extend your arms without touching the walls. There is no bench or bunk. Just a dusty floor to pace and a few spiders scuttling into the cracks.

Famed Baltimore director John Waters spent a few hours behind bars at the Northern District — but not in solitary confinement.

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

The case drew 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.

Disrobe, if need be, but behind the door;

And if again, you heed the call of art,

Rest assured, the judge will do his part.”

Waters said he doesn’t remember much about the cells at the old Northern District, other than that they were “old school” and his friend David Lochary passed him a gum wrapper 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, passes The Castle often.

“I always think of that when I go by,” he said.