One of the more disconcerting pictures in the Louvre is Hubert Robert’s Imaginary View of the Grande Galerie in Ruins. The 1796 work depicts the museum itself as a classical desolation, recalling the Palace of Domitian on the Palatine Hill in Rome: the entire roof of the Grande Galerie has been shorn off to reveal open sky, while the ground is littered with fallen debris, and peasants wander among shattered antique torsos...