FOR me it was hearing the names and the ages.

I could picture who they were as I sat inside the information centre underneath the Memorial to the Murdered Jews of Europe in Berlin. I visited the city two years ago with my sister.

We sat silently in the Room of Names listening to the tape and studying the walls as the name, year of birth and death of each person flashed onto the screens.

There were 43-year-olds, 20-year-olds, two-year-olds.

The room is an attempt to show the victims for who they were - humans - instead of numbers. The reading of all their life stories would take six years, seven months and 27 days.

There were six million Jews murdered in the Holocaust - along with Roma people, homosexuals and others seen as incompatible with the Nazi ideal - we only listened to a small amount of their stories.

It was enough to make me silent for the rest of the day, but it's not enough. Not one story can be forgotten.

I have been thinking about that visit this week as we mark Holocaust Memorial Day and 70 years since the liberation of Auschwitz-Birkenau.

It is particularly poignant because this is likely to be the last major anniversary the survivors will be with us.

Most of them are now in their 80s and 90s, and many have already died in the last 10 years.

It is still fascinating, and still shocking, and still horrific to hear their stories.

People like Freddie Knoller, now in his 90s, who, in a BBC documentary, told how he did not believe that men, women and children were being gassed and burned to death as he did hard labour in Auschwitz. Until he smelled the air.

The unimaginable sadness of the situation is laid bare when it emerged that decades later in Freddie's life, he discovered his parents had been killed in Auschwitz while he was there.

And Ela Weissberger, 84, who was 11 when she was sent to the Terezin concentration camp.

After she told her story to school pupils in the west of Scotland on Tuesday and lit a candle, she said she hoped it would inspire the next generation to "be better to each other".

It is right that Glasgow pupils were marking the event too - some were taken to see The Boy in Striped Pyjamas and The Book Thief.

We will always mark anniversaries but we have to think and talk about it more frequently.

All other victims of genocide must be known too.

We have to talk about why mass murder happened and why it has happened since World War Two. Talk about it amongst ourselves and with younger people.

The Holocaust can't be put into words, but stories can and they are all we have. They must stay alive.