In Berlin in 1942, a young man wearing the uniform of the Hitler Youth movement walked into the detention centre where Jews had been rounded up to be deported, and persuaded the camp commander that he needed Manfred Lewin. Manfred walked out - with his disguised lover, Gad Beck. But Manfred could not bear to leave behind his parents. As Gad remembered later: "Gad, I can't go with you. My family needs me. If I abandon them now, I could never be free." No smile, no sadness. He had made his decision. We didn't even say goodbye. He turned around and went back. In those seconds, watching him go, I grew up." Manfred returned to the detention centre, to deportation, and to death at Auschwitz.
Monday is Holocaust Memorial Day. I am sometimes asked if we still need to remember those who died in the Holocaust - after all, it was such a long time ago. Isn't it time we all moved on? And surely more recent events should take up more of our attention?
My answer is an emphatic "No!".
Holocaust Memorial Day was established only a few years ago, in 2000. It was instituted by international governments, convinced they had a responsibility, fifty-five years on, to ensure that their populations commemorated the "defining episode of the Twentieth Century". They wrote that the Holocaust 'fundamentally challenged civilisation'. Think what this powerful phrase means: the fact that the Holocaust took place threatens what it is to be civilised.
The systematic, planned, industrialised slaughter of six million Jews - including 1.5million children - in an attempt to wipe out European Jewry completely should be commemorated because it happened. Because cultured, industrial Europe allowed it to happen - indeed, that very sophistication and industrialisation facilitated the Holocaust. By commemorating it, we acknowledge the fragility of our society and how hard we need to work to maintain our values and humanity.
In fact, the occurrence of genocides since the Holocaust demonstrates how very important it is to commemorate the attempted annihilation of Europe's Jewish population, and all victims of Nazi Persecution. There have been genocides in Cambodia, Rwanda, Bosnia and Darfur - showing all too clearly that lessons have not been learnt from the past.
There is an even greater need to remember, inform and raise awareness of the Holocaust and subsequent genocides. Research published for Holocaust Memorial Day 2014 shows that over 50% of the UK population cannot name a genocide that has taken place since the Holocaust - the figure rises to over 80% for those aged 16-24 years.
The Holocaust - and subsequent genocides - took place following periods in which perpetrators deliberately dehumanised those they wished to wipe out. Years of persecution and segregation, use of propaganda and language to delegitimise and stigmatise, laws to separate and oppress - all were weapons in a battle to strip away individuality and personhood. As we know, in concentration camps, Nazis sought to take away individual names and replace them with tattooed numbers.
Holocaust Memorial Day is an annual opportunity to reflect on the past. Established 14 years ago by governments of 46 countries, there are now well over 2,000 activities across the UK, in community centres, civic halls, schools, libraries, cinemas and more.
Do we need to remember those who died? Remembering people who were murdered because of the community they belonged to, because of their faith or who they were, honouring those who survived - this is our act of defiance, our act of rejection of the ideology that led to the Holocaust.
Remember Manfred Lewin, who felt he could not be free if he abandoned his parents - and went with them to Auschwitz. Remember Gad Beck, a Jewish resistance fighter, who survived the Holocaust, only to return to a Germany where gay people were still criminalised and victimised. His final act of defiance was to rebuild Jewish and gay life in Germany.
Will you make your act of defiance? Take a step for Holocaust Memorial Day to learn lessons of the past, and create a safer, better future.
Visit hmd.org.uk or follow The Holocaust Memorial Day Trust on Twitter at @hmd_UK or #hmd2014