There is a region of the city where every building is tethered to the ground by large chains of every kind - iron, steel, gold, silver, and spiderwebs. The chains are anchored firmly into the ground around the buildings, but the binding is imperfect; occasionally, one structure will slip its tethers and sail off into the city. This region of the City hasn't always been like this; the chains apparently started growing there 20 or so years ago. This region of the City is distinct in being one of the few the Redcaps haven't colonized; something in it makes them unwilling to linger.