Build your cities proud and high. Lay your sewers. Span your rivers. Work feverishly. Sleep dreamlessly. Sing madly, like the bulbul. Underneath, below the deepest foundations, there lives another race of men. They are dark, sombre, passionate. They muscle into the bowels of the earth. They wait with a patience which is terrifying. They are the scavengers. They emerge when everything topples into dust.