It happened 60 years ago and for those who grew up in the post-war aftermath of the Holocaust, the horrors are ingrained on their memories. But what of today's teenagers? How much, if anything, do they know about this nadir in human history?
When Eva Clarke was born at Mauthausen concentration camp in April 1945 her mother, Anna, weighed just five stones. Eva herself weighed 3lbs. She did not move and she did not cry as she was wrapped in newspaper to protect her from the cold.
Unknown to Anna, her husband, Bernd Mathau, had been killed by the Nazis "for no reason" at Auschwitz months earlier. And her parents, siblings and cousins had all died in the Holocaust.
Today Eva Clarke, 60, who lives in Cambridge, tells her story up to 50 times a year to young people, in an effort to keep alive the memories of the Holocaust.
"The students when they listen to the real-life stories are riveted. You can hear a penny drop," she says. "It is terribly important to educate people about the effects of the Holocaust and to remember all the people who died."
But how much, if anything, do young people know or care about this low point in human history? When Prince Harry, 20, recently sported a Nazi swastika to a fancy dress party, some commentators speculated that his generation were ignorant of the atrocities of Adolf Hitler's Third Reich.
Ottillie Cheetham, 15, from Chesham, Buckinghamshire is studying for her GCSEs
We had a couple of lessons in Religious Studies in Year Nine at school and we went to an exhibition at the war museum in London which showed the history of the Holocaust.
It was really good, really interesting but it didn't make it easier to relate to, although it does bring it home.
Surprisingly few of us knew about the Holocaust, less than I'd have thought. Some people yeah, but more than I expected didn't know.
I always knew about it, for as long as I can remember. I've read about it in books and seen it on TV. I find it interesting in small doses.
I know it was about the Final Solution and they were anti-Semitic and killed lots of old people and kids and other people.
I do think it's important to remember because it was a big thing and it shouldn't just be forgotten.
In the tsunami thousands of people died because of nature, but people did this to people.
Chris Dryden, 16, from Livingston, West Lothian, is at school doing his Scottish Highers
It's been a lot in the news recently and I watch the news as much as I can. I am really interested in most of World War II.
One of my grandfathers served in the Navy, so I've heard stories throughout my childhood. I started going to France to see where the D-Day landings were and my interest gradually built up.
I think it is all very relevant, especially for young people because the issues are recent and young people need to know what happened previously so it will never happen again.
It was the idea of perfection that started it. In Germany the idea that they would become overcome by Jews because they thought they were more successful and getting rid of "inferior races".
The threat of going back is always there but hopefully, if people are constantly reminded of the drastic measures that were the Holocaust, it will always be in peoples' minds.
Jessica Bryson, 15, from the Wirral, Merseyside
We went to a talk from a survivor today. It was quite moving because he had pictures and stuff.
Some of it was new to me, stuff that happened, how bad it was. I didn't realise it was that bad and that many people were involved. The way they were treated and how nasty the Nazis were.
It is an important part of history and we don't want it to happen again. They told us there were other countries, like Bosnia, where it has happened and I hadn't had any idea.
In future I think I'll get more involved. All the people who died makes me think about them and respect them.
Jake Flynn, 16, from Brighton, East Sussex, works in a fast-food restaurant
I learnt a bit about it in history in Year 11 and we went to a museum in Greenwich but I really wasn't that interested at the time.
Obviously I think it was very harsh for all the people living in Europe, all the six million that died. That was very bad.
But I don't think anything like that will happen again - although I don't really think about it that much.
Obviously for the people who lost family members of friends they will be making a big deal of it, but I think it happened 50 years ago or whatever it was and most people aren't really bothered about it.
Shaun Smith, 17, from Shenfield, Essex, is just finishing his A-levels
I don't really know about it at all. All I know is it's to do with Jewish people getting exterminated in the concentration camps.
I would like to know a bit about it but it isn't something I am really interested in. But it is relevant for people to know what has happened in the past, history is always important.
But it is not something that I think would happen again. I think things have come on much more since then.
Cornelia Gardner, school head girl, 18, from Nottingham
I didn't know it was Holocaust Memorial Day but we have learned a lot about it at school - about the Nazis side, what happened and the way people were killed, things like that.
It did really scare me, I couldn't sleep and it made me feel sick.
I think it should be remembered because it is something that should never be allowed to happen again.
When I was 15 I went to Washington DC and visited the Holocaust Museum there.
At the entrance they gave us a card with the ID of somebody that had been killed in the Holocaust and we virtually became that person, it told us about the lives they lived, what they had to do and what happened to them.
That really brought it home.
There was one room which just had a pile of shoes from all the people who had died, and on the wall it said something like "all of our memories must be kept alive". It was so powerful.
I definitely want to get involved but I don't know how. I want to do a bit more than a minute's silence.
Catherine Clough, 17, of Bideford, North Devon, is studying three A-levels
I've read a bit about it because it's in the newspapers and everything.
It is a very interesting topic and there are many things to learn about, and I don't think we [young people] know a lot about it, I don't know the actual details.
I know it's about Jews, concentration camps and Nazi killings but that's about it.
I can recall doing it in Year Six but we concentrated more on World War II than the Holocaust itself.
We watched a programme about it and that was pretty grim. It was quite graphic.
But really it's another world. Even just thinking about the war, we have nothing to compare it to. With the war in Iraq, we aren't actually there and it's not happening in Britain.
Although we should remember it, it is world history and for the people who died and survived it should be remembered. If we don't remember it is just going to evaporate.
But some people wouldn't want to learn about it because it is so shocking.
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