The humour also reflected the grotesque, sometimes surreal, images of the time. The largest air-raid construction in Berlin was the Zoo bunker, a vast ferro-concrete fortress of the totalitarian age, with flak batteries on the roof and huge shelters below, into which crowds of Berliners packed when the sirens sounded. The diarist Ursula von Kardorff described it as ‘like a stage-set for the prison scene in Fidelio’ Meanwhile, loving couples embraced on concrete spiral staircases as if taking part in a ‘travesty of a fancy-dress ball’.

There was a pervasive atmosphere of impending downfall in personal lives as much as in the nation’s existence. People spent their money recklessly, half-assuming that it would soon be worthless. And there were stories, although hard to confirm, of girls and young women coupling with strangers in dark corners around the Zoo station and in the Tiergarten. The desire to dispense with innocence is said to have become even more desperate later as the Red Army approached Berlin.

The air-raid shelters themselves, lit with blue lights, could indeed provide a foretaste of claustrophobic hell, as people pushed in bundled in their warmest clothes and carrying small cardboard suitcases containing sandwiches and thermos. In theory, all basic needs were catered for in the shelters. There was a Sanitätsraum with a nurse, where women could go into labour. Childbirth seemed to be accelerated by the vibrations from bomb explosions, which felt as if they came as much from the centre of the earth as from ground level. The ceilings were painted with luminous paint for the frequent occasions during the air raids when the lights failed, first dimming then flickering off. Water supplies ceased when mains were hit, and the Aborte, or lavatories, soon became disgusting, a real distress for a nation preoccupied with hygiene. Often the lavatories were sealed off by the authorities because there were so many cases of depressed people who, having locked the door, committed suicide.