Geocentric model and planets were holes in invisible wheels surrounding Earth; through the holes, humans could see concealed fire. About the same time, Pythagoras thought that the Earth was a sphere (in accordance with observations of eclipses), but not at the center; they believed that it was in motion around an unseen fire. Later these views were combined, so most educated Greeks from the 4th century BC on thought that the Earth was a sphere at the center of the universe. In the 4th century BC, two influential Greek philosophers, Plato and his student Aristotle, wrote works based on the geocentric model.
National Register of Historic Places listings in Central Chicago Chicago architecture. Architect Louis Sullivan's work is represented by the Carson, Pirie, Scott and Company Building, and Auditorium Building. Though Frank Lloyd Wright worked downtown early in his career as an assistant to Sullivan - including work on the James Charnley House - his own work in the central city is represented only by a renovation of the lobby of Daniel Burnham's and John Wellborn Root's Rookery Building. At least three sites relate to the city's role in nationwide retailing. Included also are several religious buildings, six hotels, and four theaters. National Register of Historic Places listings in Central Chicago