Blue skies. Sunshine. A fresh spring breeze rustles through the vibrant green leaves of young birches and tugs at women’s skirts. Children in shorts and dresses romp around a playground, scamper back and forth, and kick a ball about (Fig. 0.1). Mothers and fathers push strollers through the bright streets. It is hard not to notice how many children there are; the town seems so young, the spring day so beautiful. Even the two civil defence officials pacing through the idyll could not appear more relaxed if they tried. And yet – with their drab green overalls and grey-green respirators, they look as if they have come from another world. When someone enquires as to the reason for these strange outfits, they pause briefly to explain that it’s an exercise. It is just an exercise.