 One of the most spectacular and imaginative aspects of The City of the Sun, which immediately struck its readers, are the painted walls of the city. Apart from enclosing and protecting the city, the walls are also the curtains of an extraordinary theater and the pages of an illustrated encyclopedia of knowledge. The walls of the palaces are painted with images of the all the arts and sciences. Starting with the wall that holds up the columns of the temple and gradually descending in large circles, following the order of the planets from Mercury to Saturn, we encounter illustrations of the heavens and the stars, of mathematical figures, of every country on earth and of all the marvels and secrets of the mineral, vegetable and animal worlds, until we arrive at mankind: on the internal wall of the sixth circle the mechanical arts and their inventors are represented. Campanella was greatly interested in all ingenious discoveries, and in The City of the Sun he provides many examples of curious inventions, such as vessels able to navigate without wind and without sails, and stirrups that make it possible to guide a horse using only one’s feet, leaving one’s hands free. On the external wall legislators are depicted; and it is here, in “a place of great honor”—but along with Moses, Osiris, Jove, Mercury and Muhammad—that the Genoese sailor recognizes Christ and the twelve apostles. Knowledge is not enclosed in books kept in separate places such as libraries but is openly on show to everyone’s eyes. Visualizing in this manner promotes a quicker, easier and more efficient form of learning, in that it is connected to the art of memory, which underlines the evocative and emotive power of images. From a tender age children run around in this theater of knowledge, appropriately guided and following correct itineraries, so that they learn joyously, as if playing a game, without effort or pain.