We want to get to the place where history happened. We feel nearer antiquity when we stand in the Roman Forum, though we have only moved nearer in space, not in time. We are moved by an empty field of grass because a Civil War battle was fought there once. We travel great distances to museums to see original paintings that we have seen as clearly and without the crowds in reproductions, because our eyes must rest on the canvas the master's hand touched.

But does the body of history lie in the shrines where we seek it? Space is as restless as time. After one hundred fifty summers of new growth, the grass in the Civil War field is not the grass the soldiers stood on. The museum's famous paintings glow with oil pigments from the restorer's, not the artist's, brush. In the Roman Forum, we walk upon the dust from prior visitors' shoes and breathe the air that they, not the ancients, exhaled. Caesar's dust has likely disappeared from Rome, but we may find it in our garden when we get home, if the winds of two millennia have blown it there.