With a stone head, a ten-metre-long creature in crumbly white chalk is outlined all over the sidewalk. It stretches and stretches from under the brick side-wall of the church of S. Rocco over the pavement and into the street and then points to the Ara Pacis pavilion. What is it? A ghost, a river god? Is it drawn by a wise child, a madonnaro, or someone brave and strange? I wonder, and then amble on. Some weeks later, walking from Via della Scrofa towards Piazza del Popolo, remembering the apparition with amusement, I expect it to be gone, washed away by recent rains. But lo! Here it is freshly outlined again, stretching mysteriously over the cobblestones. Now I notice scruffy funky objects too, scattered here and there over the stone posts surrounding the mound of the emperor Augustus