The Berlin Wall is long gone. Its notorious prison still stands.

On Feb. 5, 1989, Chris Gueffroy was the last person to be shot dead trying to flee East Germany over the Berlin Wall. And it was to the Keibelstrasse prison, in the shadow of the wall, that his mother, Karin, was summoned two days later “for the clarification of a fact.”

She told a policeman there that her 20-year-old son was “like a wild colt, you can’t hold him back,” she later recalled. The East German policeman told her that Mr. Gueffroy had “committed an assassination attempt on a military officer” and had “died a few hours ago.”

The history of Keibelstrasse prison was intertwined from the start with the story of the Berlin Wall, which was finally breached 30 years ago on Nov. 9, 1989. East German leader Erich Honecker used the prison as a command center from which to orchestrate security installations for the wall even as it was being built in 1961.

Today the forbidding four-story building remains closed to the general public, but it has been opened to school tours as a memorial to Germany’s history of division and as a warning to young people about the forces behind that history.

“This is where people were broken,” Berlin’s education senator, Sandra Scheeres, reminded her audience as she opened Keibelstrasse in February.

A peek into old East Germany

The penitentiary’s 140 cells are small and dank, its furnishings with the thin, poorly made look common to so many East German artifacts. Scrawled graffiti on the walls speaks to the hopes of East Germans who chafed against dictatorship: One is a drawing of a cityscape above a misspelled caption, “New Yorck City – The Big Dream’s.”

As soon as the wall across Berlin had been built – mostly out of hastily assembled cinder blocks – Keibelstrasse began to serve its new purpose. Anyone caught trying to cross the “Anti-fascist barrier” was taken there by the notorious East German People’s Police, Volkspolizei, known as VoPos.

“The VoPos used to arrest people hanging around the Berlin Wall who were suspected of trying to escape,” says Jochen Staadt, an expert on East German history at Berlin’s Free University. “They were interrogated in the Keibelstrasse. Then they would be handed over to the Ministry of State Security [Stasi].”

“In principle there was no such thing as a political prisoner in the GDR [German Democratic Republic]. Anyone against the system or who wanted to escape was a criminal,” says Mr. Staadt.

Sometimes, that included rock fans.

In October 1969, thousands of young East Germans flooded into the capital, drawn by a rumor that the Rolling Stones were going to perform on top of the Springer publishing building in West Berlin. The Springer skyscraper was tall enough that East Germans would be able see the British rockers from their side of the wall.

The Stones never played.  But that didn’t stop the VoPos from rounding up disappointed fans and branding them as “anti-social” and “rowdies.”

“Once they arrived in Berlin, hundreds were arrested and many of them were kept here at Keibelstrasse. The whole place was full,” says Jan Haverkamp, an education officer at the jail. “Boredom was a big factor. You were supposed to sit there and think about what you’d done,” he says. Reading material was thin – Karl Marx’s “Das Kapital” was encouraged and every day inmates were given copies of “Neues Deutschland,” the ruling party’s mouthpiece.

Jailed for opposing the regime

Toni Krahl, singer with the rock group City, recalls being hauled into Keibelstrasse for protesting the Soviet invasion of Prague in 1968.

“The wall was very present. It was a bit like living in a port city – at a certain point you could go no further. Everyone had links to people who live in the West, who had gone over,” he recalls.

“I thought I was there for the morning. It turned into an interrogation. At 2300 hours my arrest warrant was read out for state subversion,” he says in an interview, every inch the veteran rock star with his shaved head and tinted glasses.

Mr. Krahl was sentenced to three years. Daily life was rough, and exercise in the cells was not permitted. Pillows were never changed and toothbrushes handed down from previous prisoners. “Then there were roll calls. You stood with your back to the window and called out your name, number, and the phrase ‘No unusual occurrences.’”

“I served 100 days, 100 nights. And then I was out. As unexpectedly as I went in,” Mr. Krahl recalls.

Witness to intimidation and beating

Florian Havemann was first brought to Keibelstrasse in 1966 for wearing a top hat, waistcoat, and frock coat to celebrations of an anniversary of the GDR. The authorities were not amused by his sartorial satire.

“They thought by wearing a top hat I was trying to drag the GDR into the grave,” he says in an interview at his art gallery at Friedrichstrasse, one of the old Berlin Wall border crossings.

“It had a terrible reputation. Everyone knew what the Keibelstrasse was. There was a young man who leaned against the wall. He was supposed to stand up straight, away from the wall. They beat him up very badly. That was the first evidence of police terror I’d seen.”

Mr. Havemann recalls his costume as a revolt against the norms of the East German society he grew up in.

Such expressions of revolt landed thousands in Keibelstrasse jail over three decades. And since the wall came down, there have been different reactions; some people in the former East – especially older citizens – feel Ostalgie for the good old days. Some have flourished in the newly democratic atmosphere. Others have shifted from the hard left to the hard right.

“I tried to push for democratic reforms back then. People had different expectations. No one thought the GDR would just disappear like that!” says Mr. Krahl. “In the West, nothing changed. For the people here, the initial euphoria wore off. Some were disappointed. But others have done well. There is more than one side to this story.”