The knowledge from Faust’s book was translated into an active solar building program in the 1820s through the 1850s in Lower Bavaria, Hessen and Prussia. . . Faust’s ideas were implemented in Bavaria, where the first solar schools were built. Faust’s Sonnenstadt plan was an ideal solar city, and the frontispiece to his book became a reality as the inspiration for the rebuilding of La Chaux-de-Faunds, Switzerland in the 1850s. In 2009, the United Nations chose the city as a World Heritage Site.