In a far corner of the "new" Jewish cemetery (opened 1902) in the Polish city of Wrocław, Piotr Gotowicki is hacking away at the thick ivy that has grown over a gravestone.
It is not just any old gravestone, as Piotr knows full well. He has consulted the record book, detailing where each of the cemetery's 12,000 bodies has been buried. And as the gravestone is uncovered, so is the name engraved on its surface - "Georg Cohn, 13.12.1887-13.4.1938".
Georg was my mother's adored father, who died of a heart attack two weeks before her 17th birthday. My mother, his only child, emigrated to Britain the following year; his wife, Ilse, was deported and shot in Kaunas, Lithuania by the SS in 1941.
So the grave must have lain untended and forgotten for more than 70 years. And now, three days after honouring my grandmother Ilse at the scene of her death, here I am in the cemetery, honouring her husband, my grandfather. This is truly a journey back to my family roots.
My mother never returned to her home town. When she left in 1939, it was called Breslau and was in Germany, with German inhabitants. Since 1945, the city has been called Wrocław, it is in Poland and its inhabitants are Polish.
The address my mother lived at became a home of last resort for the city's Jews
Is anything left of its previous identity? There are still a few beautiful old buildings, the ones that were not destroyed when the Soviet army pulverised the city at the end of the Second World War, and on some of the buildings you can see the faded German lettering identifying their previous owners.
But otherwise, no, this is a Polish city with a strong Polish identity. The Germans who used to live here were expelled at the end of the war, and their place taken by Poles from, among other places, Lviv, which had been Polish before the war, but which was handed over to Ukraine, ie the Soviet Union, in 1945.
In her memoirs, my mother remembered Breslau as "very dirty, with big houses". She described her childhood home as "a very large flat, with a huge balcony", overlooking a park.
I tracked down the address, only to discover that the street has vanished, along with all its grand, turn-of-the-century apartment blocks. But old photographs reveal that it was lined with chestnut trees, and yes, the trees are still there. So are the trams that run along the main boulevard at the end of the street.
But I also discover something that I suspect my mother's parents never told her. The address she lived at between 1933 and 1939 became a home of last resort for an increasing number of Breslau's Jews as their property was confiscated by the Nazis. At the cemetery, Piotr Gotowicki tells me that he has the burial records of a great many people for whom the address was their last registered place of residence.
My mother always thought that her parents moved there because it was in a better part of town - the truth may be that it was the only place they could go.
At the offices of the city archives, I fill out a form detailing the names of my Breslau forebears. When I return a couple of hours later, they have dug out and photocopied my grandparents' marriage certificate - November 8 1913, which means my grandmother was just 16 years old on her wedding day - my mother's birth certificate, and my grandfather's death certificate. All in copperplate German script, which makes them hard to read. But I had never expected that the records still existed, let alone that it would prove so easy to track them down.
There is one other place I want to visit while I am in Wrocław, the Schiesswerder, or entertainment palace cum beer garden to which my grandmother was taken after her arrest by the Gestapo in November 1941. But it too has gone, and in its place is the ugliest coal-fired power station you can imagine.
Nearby there is a street lined with dilapidated tenement buildings; soon they will be gentrified and sold, presumably, to bright young Polish designers or advertising executives.
And so old Breslau continues to give way to new Wrocław. I cannot help wondering what my mother would have made of it.