Along the way, I also encountered a family mystery that remains shrouded in Holocaust history.

Locating the graves was easy enough, but on the way I learned the answers to questions that had rankled for years.

First and foremost, why had the Nazis left untouched this massive testimony to a people that they were determined to eradicate?

Especially, since even as only a practical matter, the Nazis had maliciously destroyed Jewish cemeteries throughout Germany and the rest of Europe and used the tombstones as building materials.

“When you study Jewish life in Berlin, you find that many Jewish sites in Berlin were never destroyed by the Nazis,” explains our cemetery guide Robert Sommer, a German with a PhD in Holocaust studies.

“The reason is simple and still hard to believe — the Nazis never had absolute power over Berlin.”

Sommer belongs to that post-war generation of Germans scarred by the Nazi era and determined to wrestle with the past, not bury it.

“I visited Auschwitz on a school trip, and I was devastated,” he recalls. “It was life changing. How could this have happened?”

He is leading us through the more than 100 acres of the Weissensee cemetery, far from the tourist path of central Berlin.

Tourism operators in the city offer a number of Jewish-themed excursions, but none come here.

Instead, they visit the understandably better-known city centre synagogues that survived the war and the relatively recent impressive Holocaust Memorial and Jewish Museum.

We wanted a different tour, a bit more offbeat and the family graves seemed like a good starting point.

Sommer meets us after a light snowfall at the Holocaust memorial plaque in front of Weissensee’s original yellow-brick portico. Inside, we pass by the burial place for some 90 Torah scrolls desecrated during the war as Sommer steers us through the narrow paths laid out in a grid to connect the some 115,000 graves.

One needs a map here, available from the cemetery, but Sommer has done his homework and knows the exact location of my great-grandparents, Clara and Felix Ginsberg, who died in the 1920s when Hitler was still in the political wilderness.

The only hints of war damage can be seen on some tombstones, bullet pockmarks that serve as reminders of the intense street fighting as the Soviet army subdued the capital.

“Jewish life in Berlin was so strongly embedded that the Nazis could never destroy it entirely,” explains Sommer.

Some 160,000 Jews lived here when Hitler took power in 1933, about one-third of Germany’s Jewish population.

Not only were their numbers large, but they were well integrated into the community. Many had married non-Jews.

They lived throughout the vast city. There were no Jewish ghettos that the Nazis could easily seal off and round up its residents.

At the same time, Berlin was a notoriously open and left-wing city where the Nazi vote always badly trailed that in the rest of the country.

Indeed, Berlin once had a Jewish police chief, and the Nazis were even banned for some time from the ballot in Berlin's local elections.

As we walk, Sommer describes other seemingly miraculous examples of Jewish institutional survival in the Nazi capital.

Berlin’s Jewish hospital, with its Jewish medical director, continued to operate throughout the war and had some 370 Jewish patients when liberated in 1945.

We learn of Otto Weidt, Berlin’s Schindler, who protected blind and deaf Jews as workers in his brush and broom factory.

And we hear how a bunch of unarmed women defied a SS squadron.

The incident was sparked by the round-up of some 2,000 male Jewish factory workers for deportation in 1943.

Their gentile wives immediately took to Rosenstrasse, the street where they were being held, demanding their release.

Faced with the prospect of violence against unarmed women, some with babes in arms, or releasing their loved ones, the Nazis blinked.

“The war was not going well, and the authorities feared an incident might even provoke a public uprising,” says Sommer.

Freed — some were even returned from concentration camps — the husbands went underground and many survived the war.

During the war, Weissensee continued to serve the Jewish community, with religious burials until at least 1944.

Its large expanse and some of its crypts served as hiding places that saved many Jews from deportation and near-certain death.

The cemetery itself clearly demonstrates the Jewish community’s assimilation into German life.

Weissensee was never for the Orthodox, but in the first decade or so after it opened in 1880, tombstones remained strictly traditional.

Monuments were simple, small slabs with Stars of David and Hebrew inscriptions.

But by the turn of the 20th century, the monuments had become more ornate, Magen Davids were rare and birth and death dates were for the most part recorded in the Christian, not Jewish, calendar.

People showed off their wealth by building elaborate tombs and art-nouveau mausoleums.

Among the designers were the soon to be famous Walter Gropius and Ludwig Mies van der Rohe. (Relying on this rich history, the city of Berlin is lobbying to declare Weissensee a UNESCO World Heritage Site.)

My great-grandparents’ tombstone does have a small Magen David atop. But when we clear off the snow, we are in for a surprise.

Below their names are those of three others, the Ginsbergs’ three children who died long after their parents — and perished far from Berlin.

Two of them, their adult sons Arnold and Walter, died in the Holocaust. Arnold lived in Berlin, was deported in 1943 and died at Auschwitz. Walter lived in Lodz with a wife a daughter.

His trail ends at a Hungarian labour camp. The third child, their daughter and my grandmother, managed to evade the Holocaust and died before the end of the war, in New York in 1943.

Therein lies another family tale that provides another perspective on Nazification.

That grandmother was living in Vienna with my mother when the Nazis swallowed up Austria in 1938.

Banned from normal activities outside their apartment on one of Vienna’s toniest streets, they sought refuge in, of all places, in Berlin, the city where my grandmother had been raised.

There, Jews were still allowed to go to the cinema, continue with their education and go for walks in the park without wearing a star stitched to their clothes.

My teenage mother went to high school and was allowed to live a less restricted life while they waited for their American visas.

So how did the names of my grandmother and her brothers get added to their parents’ tombstones? Who did it and why?

Back home in Toronto, I emailed the cemetery, which replied that the names were added in 1957 and that it had no further information.

I turned to Berlin’s official Jewish community, which said it had nothing to do with inscribing the names and added that only the cemetery would have such records.

Back to square one, and, so it seems, the mystery remains.

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