The Art Institute of Chicago, which in 2009 completed a modern wing designed by the acclaimed architect Renzo Piano, houses 260,000 artworks and artifacts. Though for now these wonders remain behind closed doors, 600 of the museum’s most important holdings—including Mary Cassatt’s The Child’s Bath, Cézanne’s The Basket of Apples, and Julia Margaret Cameron’s portrait of her niece, the beauty Julia Jackson—are here for you to take a gander at. —E.C.