I had an earworm yesterday. You know earworms:  those songs that get stuck in your head? Well, I had Danny Boy, sung to the tune of the Horst Wessel Song, in my head.

I mentioned it on Facebook, and my friend Sally asked, ‘why do you know the Horst Wessel Song?’

I’ve given the question a good deal of thought. When I was posted to British Forces Germany as Staff Officer for Counter-terrorism I spent a good deal of time within visiting distance of former concentration camps. Indeed, the British garrison towns of Hohne, Celle and Fallingbostel are around and on the site of Bergen-Belsen Camp. I never visited.

Smiling women holding aid parcels stand outside a hut at Bergen-Belsen concentration camp at its liberation by British forces.

Inmates of Bergen-Belsen liberated, April, 1945

Battlefields are impossible to understand without walking the ground, and I’ve visited many. I’ve never visited any concentration camp or death camp. For me, what happened there is significant, but unlike a battlefield the understanding isn’t inherent in the ground. Much the opposite: the death camp system as an industrial process could have been run anywhere in the Third Reich with little operational difference.

Nazi concentration camps and death factories were built close to relevant population centres and railheads. As the process of genocide moved from a retail to a wholesale process the location of the population to be murdered became less important and the location of railways became more important. The railways were, however, ordinary Deutsche Reichsbahn railways. The kilometre leading to the gates of the killing centre Auschwitz-II were identical to the kilometre leading to the gates of the synthetic rubber factory Auschwitz-III.

The process of mass murder was enacted in the concentration and death camps, and it’s important to understand them. It’s important to understand that the camp where Shimon Peres’s father was a British prisoner-of-war (Auschwitz-III) is connected with the camp where the Jewish population of Hungary was briskly slaughtered (Auschwitz-II).

I thought they were whistling the Horst Wessel Song, but I was wrong. It was Lili Marlene.

The mechanics of enslavement and murder are not, however, the most important part of the story. Genocide per se is a common enough occurrence in human history. It is important to consider each incidence of genocide as a unique event in order to understand it. Else it becomes, like war, a grim but necessary part of human interaction.

The exceptional thing about the Shoah is that a nation could simultaneously love Heinrich Heine’s Lorelei and hate Heine’s Jewishness. A people who could be moved to tears at the theatre could dust off their hands and turn to the workaday annihilation of their neighbours. A veneer of highly-evolved civilisation, however highly polished, doesn’t change human nature.

That exceptional thing isn’t there to be learned in the ruins of Auschwitz, the carefully-maintained huts of Dachau or the places near Hanover where the British Army is leaving after half a century keeping the Germans in hand. The exceptional thing is to be learned by knowing how a psychotic Austrian corporal with hypnotic dark blue eyes could turn a nation into his robotic followers.

Nazi stormtroopers salute their colours, Tempelhof Airfield, Berlin, 1933

Nazi stormtrooper colour ceremony, Berlin Tempelhof Airfield, 1933

And that’s why I know the Horst Wessel Song. The first time I saw The Longest Day there was a scene with two German soldiers whistling as they marched. I thought they were whistling the Horst Wessel Song, but I was wrong. It was Lili Marlene.

The first time I saw Casablanca there was a scene with Germans in Rick’s singing as they drank. It’s a brilliant scene with everyone joining in to drown the Huns out. I thought they were singing the Horst Wessel Song, but I was wrong. It was Wacht am Rhein.

I was chilled to realise that I didn’t know the theme music of the Holocaust, the marching song of the Sturmabteilung, the song which was tacked onto the Deutschlandlied to create the Nazi national anthem. I didn’t recognise the song that the brownshirts sang as they activated the dark quiescent corners of the Teutonic brain and turned the German people into enthusiastic practitioners of genocide. Since then I’ve gone out of my way to hear the Horst Wessel Song enough times to learn it.

I learned that song so that I’ll know it when I hear it.