When pupils ask a question like this, teachers need to be able to reply fully and frankly in a way that ensures succeeding generations never forget the Holocaust. That is why David Newnham joined 150 teachers on a day-trip to Auschwitz. The horror of it will stay with them forever, but the lessons learned will equip them, and their pupils, to come to terms with the crimes of the century, from the Holocaust to this year's atrocities in Kosovo
I am in one room and he is in another. But there is no mistaking the edge to my son's voice as his mother buckles him into a pushchair and wheels him towards the door. "Where are we going, Mummy? Where are we GO-WINGGG?" For him, the answer is quick and simple. The shop. He is going to the end of the road to buy yoghurt, bread and milk. But as the door shuts behind them and the rattle of wheels recedes, other voices fill my head - other answers, hollow and frightened. "To the country," one says. "For a holiday," comes another. And I imagine them, mocked and taunted, on that wide open platform. Mummies and daddies. Little boys and trains.
Why have the voices come to me just when they have? Because last month I visited the Auschwitz-Birkenau concentration camps with a party of teachers - the first such visit organised by the Holocaust Educational Trust to help those charged with the uneasy task of telling children exactly what the lady on the television means when she says ethnic cleansing reminds her of Hitler's Final Solution.
Mine, I don't doubt, is a common reaction to such a day-trip. Weeks go by, and then it comes to you like a knee in the stomach one sunny Saturday morning. The trigger may be a report from Kosovo or a scene in a Teletubbies video. For me it is the voice of a bewildered two-year-old.
We were broadly of a generation, the 150 teachers - half of them history teachers - who, together with a handful of MPs and other guests, filled an Airbus and flew to Krakow. We shared a background of post-war documentaries, war crimes trials and families who remembered. Many had attended a preliminary seminar to hear Holocaust survivor Trude Levi speak of her experiences.
We had looked at the maps, read the poems and diaries, studied the photographs and seen Schindler's List. We were sombre but steeled. We knew what to expect.
And there, sure enough, was the electrified barbed-wire fence, dead now, but still hanging from its ghastly concrete posts. Inside each barrack house, mountains of human hair, of shoes and specs and shaving brushes, of leather suitcases and wooden legs, lay eternally in wait, ready to trip up any one of us whose emotional defences were not sufficiently well-armed that morning.
Here was a gas chamber 210m square into which batches of 2,000 adults and children would be driven with cudgels and dogs. And here were the disconcertingly modern-looking cans of duck-egg-blue pellets that came from the Farben chemical factory up the road. We had spotted it from the coach, still pouring smoke from its red-striped chimney stacks.
Down the road at Birkenau we saw the railway line passing through the arched gatehouse that looks disarmingly like an English out-of-town supermarket. And we noted how the track that had brought Jews to this place from 28 European countries - from Oslo and Rhodes, from Venice and Belgrade - continued to the very threshold of the extermination blocks, so that thousands of people could be processed into fertiliser for the local farms with a minimum of fuss. In May and June of 1944, 25,000 people a day were killed and disposed of in this way.
We had done our homework. We were thoroughly prepared for the facts that our grim-faced Polish guides tossed at us. "On our left in just a moment, the execution wall where thousands died undocumented deaths. On our right now, the building where Mengele carried out medical experiments on gypsy children.
"In each of these draughty wooden huts, 700 people at a time died of typhus. In winter, when temperatures outside were -30xC, they were forced out into the frost and snow by lice. And in this experimental oven here, 70,000 corpses were burned."
The concrete roof beams were still blackened with their soot. Even the crosses that sprouted provocatively against the camp walls - symbolising, it seemed, nothing more or less than the enmity between Christian and Jew that lay at the heart of this place - even the crosses and the accompanying music blaring from the adjacent Carmelite monastery came as no surprise to those who kept an eye on the headlines.
Only the birdsong that followed us from block to block was truly news to us. Everything else we seemed to have heard before.
"But hearing is not like seeing," said Barry Marcus, the rabbi who accompanied us on the trip. As we stood amid the dynamited remains of Birkenau's concrete death factory, nobody was arguing with that.
It was a line repeated three weeks later by the Holocaust Trust's education co-ordinator, Rosie Harris. This was the post-visit seminar in London, and she was addressing the still subdued group on the subject of "Lessons from Auschwitz". Traditionally, she said, teachers are cautioned against subjective involvement with their materials, but the Holocaust demanded entry into the event.
"Hearing is not like seeing," she said. "Our aim was to help make you into better Holocaust educators - to add another dimension to your future teaching that you can't gain simply from reading about it. I hope you can take some of it back to classrooms and take your Holocaust education beyond the mere fact and into the wider issues."
It is, of course, self-evident that anyone given the job of teaching about the horrors of the Holocaust will do so with even more conviction if they have visited a place such as Auschwitz and been overwhelmed by the sheer scale, if nothing else, of what Rabbi Marcus called "the installations for mass murder".
"A profound experience that will resonate through my life, my work and thinking," was how Tim Davies, deputy head of Woolwich Polytechnic Boys School in south London, described the visit. Jim Hunston, head of history at St Mary's High School, West Croydon, spoke of returning to England "a pilgrim, having experienced at first hand the legacy of the evil some men do to others in pursuit of their inhuman goals".
Rosie Harris insisted there was more to Holocaust teaching than simply teaching about the Holocaust. There were, she told the seminar, many "civilising lessons" that should be spun from the historical events: lessons about racism and the nature and history of anti-semitism, and lessons about tolerance and respect for other people.
"Studying the Holocaust can help students see how racist ideas can be seductive," she said. "It can teach them about concepts such as prejudice, scapegoating, stereotyping and nationalism - that loving their country and being proud of their country and supporting their country's football team is one thing, but that when nationalism goes further and starts to exclude groups within a nation, it becomes dangerous."
Older students, she said, might debate issues such as free speech, or study the psychological and socio-political conditions that allowed anti-semitism to flourish. Even very young children could draw moral lessons from the Holocaust: lessons about bullying ("you don't just walk by and allow someone to be picked on in the playground"); conformity ("we can teach our children that conformity is not always a good thing"); and sticking up for others ("the lesson to be learned from rescuers such as Oscar Schindler is that one person can make a big difference".
But there were, Ms Harris warned, a number of pitfalls awaiting Holocaust educators, and experience had shown that poor teaching of the subject could be worse than none at all. Lack of caution over stereotypes could lead to children hating all Germans: "They must be told that not all Germans were Nazis - that there were resistance organisations and there are anti-Right demonstrations happening in Germany now."
Similarly, there was a danger of glamorising the power of the Nazis, with children ending up admiring Hitler. "It's important to show how the Nazis achieved power by manipulation," she said.
Too much time spent on Holocaust studies could lead to boredom, and a feeling among students that they were being forced to adopt a particular point of view. "They can end up subscribing to a contrary attitude," warned Ms Harris.
Showing films and videos could cause problems, unless the material was chosen carefully and with a particular class in mind. For while footage of concentration camps might be a convenient alternative for teachers unable to invite a survivor into the school, younger children might find such material disturbing, and "voyeuristic teenagers", already over-familiar with explicit videos, could fixate on the violent visual images.
And what of denial? None of us who toured the Auschwitz museum could have failed to notice the emphasis that each explanatory notice gave to asserting that the Holocaust actually happened. The mountain of human hair that never made it to the textile factory, for example. Samples taken from the hair had been found to contain traces of hydrogen cyanide, the chief constituent of Zyclon B, the chemical used to gas prisoners in their millions.
"There were some disturbing opinion polls in 1993 in the UK and the US," said Rosie Harris. "In the UK, seven per cent of adults questioned believed the Holocaust had not happened. In the US, 22 per cent believed there was a possibility that it had not happened.
"A lot of educationists say the issue of Holocaust denial should not even be mentioned in the classroom. Others argue that you've got to show both sides. But with the Holocaust, people can't be completely objective. You've got to put your own stamp on things."
One teacher who was more determined than ever to put his stamp on Holocaust material wrote to the trust on his return from Poland. "Whereas I do understand why Germany has made it an offence to deny the Holocaust," said Michael Hornsby, of Lockyer's Middle School at Corfe Mullen in Dorset, "I am not sure that such censorship is the answer. The solution is to educate people so they can see for themselves the lies behind the claims.
"I am not saying that such ideas should be debated (thus giving them an unwarranted dignity), but clearly and firmly rejected. If I came away with anything from this trip to Auschwitz, it was the resolution that this was precisely my task as a Holocaust educator."
My own return to Britain was marked by a conversation with a taxi driver which bore out the necessity of Holocaust education. Where had I been? Poland. On business? Yes and no. Anywhere nice? No. Where then? Auschwitz.
The driver was young - early 20s, I'd say. And he was clearly well-read, even knowing that Jews had been expelled from English cities in the Middle Ages in murderous pogroms instigated by the ruling class.
He knew, also, about Holocaust denial. In fact he raised the subject. "There are some people," he said, as we left the airport car park and headed for a city still recoiling from the nail bomb explosions, "who say that none of it ever happened. Personally, I believe it did."
The Holocaust Educational Trust works in schools and higher education to provide teacher-training workshops and lectures, teaching aids and resource materials. It also produces academic research on Holocaust-related issues and was responsible for ensuring Holocaust education was added to the national curriculum for history in 1991 for key stage 3 students.
Last year the trust published 'Britain And The Holocaust' by David Cesarani, and its 1997 resource pack, 'Lessons Of The Holocaust', has been bought by more than 1,000 schools.
The trust has worked with the Council for Christians and Jews to produce a guide for teachers in religious education, available soon. It also intends to publish materials to help teachers incorporate the Holocaust into citizenship programmes. It hopes to take more teachers to Auschwitz and is also planning a new initiative to take sixth-formers to see the camps. Details: The Holocaust Educational Trust, BCM Box 7892, London WC1 N3XX. Tel: 0171 222 6822.