Tonight’s episode takes place at the 1893 Columbian Exposition, also known as the Chicago World’s Fair. The promo ads trumpet an appearance by Harry Houdini, but there are other things from this particular fairground well worth celebrating. The world’s first Ferris wheel, for example, and a public exhibition by Eadweard Muybridge of his zoopraxiscope, showing some of his motion studies of animals, and naked women, in motion. And Helen Keller, who was taken to the Exposition by