The photograph comes from my cousin Ada in Israel. It must have come to her from our grandmother Adele, whose handwritten annotation on the back says just "Hansi Franz 1933."

In that year, as we now know, Europe began its descent into the nightmare of Germany's Third Reich. The touring party we see today knew nothing of the fate they were going to escape, confident in their elegant leather coats and their sporting plusfours.

My parents Hansi and Franz are on the right. On the left Walter Erston recognises his parents - my mother's sister Lisl and her husband Herbert. But who is standing between the two sisters?

The context, and the figure's height and build, suggest their brother Stefan Bauer (as does the impatient inability to keep still for the photographer). But he seems to be wearing spectacles, which Stefan never did until he had to wear reading glasses in his seventies.

So who is he? Lisl is the only survivor, now approaching her hundredth birthday and, as Walter says, "holding (sort of) her own." Will Walter get the chance to see if she remembers? Perhaps one of the lessons of history is that sometimes we just don't know.