One day, Ferdinand Cheval, a French postman, came across a stone at Hauterives near Lyon, and was fascinated by its strange, evocative shape. He spent the next three decades collecting stones, shells, and fossils, and used them to build the Palais ideal. Cheval's palace is one of many works of architectural fantasy in this book, the result of over 20 years' research by celebrated architectural photographer Deidi von Schaewen. Like Cheval, the creators of these extraordinary worlds simply started building, with no rules to guide them and, in most cases, no previous artistic experience. These fantasy palaces, bizarre sanctuaries, and colorful sculpture gardens seldom follow a plan. Often the artists continued building for many years, sometimes until their dying day. Their work is impossible to categorise: Art brut, architecture with-out architects, self-taught art, fantasy architecture in the tradition of Piranesi, non-academic architecture, Outsider Art - none of these definitions quite encapsulates this worldwide phenomenon. Eccentric hideaways like the Tour de l'Apocalypse in Belgium, the Junkerhaus at Lemgo or the Owl House in South Africa appear alongside Simon Rodia's Watts Towers, which dominate the cityscape of Los Angeles. To venture into this world is to immerse oneself in the collective unconscious. The addresses of sites open to the public are listed in the appendix.