A couple of years ago my way to work passed through the so-called "Pissallee" behind the Berlin train station Zoologischer Garten - a terrible, derogatory name for a street in Charlottenburg inhabited by homeless people, the walkway usually packed with tents, makeshift beds, blankets, shopping carts and bags full of stuff to live on scattered all around, so much so that sometimes you didn't really have space to walk. One evening on my way to the train station I saw from the corner of my eye a sleeping bag - nothing unusual in this street - which looked empty to me the way it was thinly spread across the floor. Just as I was passing, it started moving and wriggling around like an earth worm, giving me for a split second the impression the empty sleeping bag is doing this eerie squirmy dance. In that split second I felt such a dread in me, felt my stomach drop and my spine chill with such a force that it threw me off for a moment and I felt the need to first collect mysel...