In the second of today's blog posts, journalist Hugo Rifkind recalls what he saw on his visit to the Nazi concentration and death camp and how this made him feel.

The thing about Auschwitz-Birkenau, prosaic as this might sound, is that it's big. Like, really big.

The original Auschwitz - little Auschwitz, you might call it - is nothing much to look at. Just a converted barracks; something of an anti-climax, really, when you pass under the notorious sign and look around, and see... nothing much. Anything could have happened here, and the things which did happen, well, they could have happened anywhere

Then you go to Birkenau, built when the plan was fully up and running, and original Auschwitz clearly couldn’t cope. Because those Nazis, well, you can tell they were in a hell of a bind. At little Auschwitz - bijou Auschwitz, you might say - there just wasn’t enough room. No matter how much they starved people down, crammed them together and killed off the weak... nah. It just wasn’t going to work. Not even with all that big, curly, Jewish hair - my hair - shaved off and stored elsewhere. Not even when they started shoving them in cupboards, for days. Too many to kill.

So, Birkenau. This isn’t just a death camp, like other Auschwitz - cutesy Auschwitz - down the road. It’s an industrial death camp, built for purpose. You know when you read about those vast Chinese factories, and you wonder exactly how vast they can truly be? This vast. So vast that it takes you a good, solid, healthy hike to get from one corner to the other. Train tracks through the door, and huts, and huts, and huts. On and on.

That, for me, is what has lingered in my mind about Auschwitz. More, even than the rooms full of shoes and hair, in which you don’t quite want to breathe, in case a bit of them - a little bit of contaminant dust; a mote of pure distilled horror - should get past the glass screens, and down your throat, and lodge inside you and never leave. More, even than the things which look like pizza ovens, and of course - of course - are not.

Just the size. Just a treeless plain, which seems never to end. Lots of work went into this. Lots of people knew about. It can’t have been a secret. You might as well try to keep Milton Keynes a secret. It’s 69 years since it was discovered, but for something so big, the word “discovered” doesn’t quite seem to work. I prefer “acknowledged”. Auschwitz-Birkenau is the incarnate horror of what humans can do.

We’re humans. We could do it, too. Nothing special about them. You go, you see, and you acknowledge that horror can happen, and it can be vast, and that people can live just down the road from it, and pretend it isn’t there. And then you swear to yourself that you won’t ever allow yourself to forget - although a better word, really, would be “suppress” -  that this can happen, and did happen, and could, should we ever allow ourselves to stop talking about it, happen again.