Geocentric model work, the "Almagest", was the culmination of centuries of work by Hellenic, Hellenistic and Babylonian astronomers. For over a millennium European and Islamic astronomers assumed it was the correct cosmological model. Because of its influence, people sometimes wrongly think the Ptolemaic system is identical with the geocentric model. Ptolemy argued that the Earth was a sphere in the center of the universe, from the simple observation that half the stars were above the horizon and half were below the horizon at any time (stars on rotating stellar sphere), and the assumption that the stars were all at some modest distance
National Register of Historic Places listings in Central Chicago National Register of Historic Places listings in Central Chicago Currently there are 124 National Register of Historic Places listings in Central Chicago, out of 354 listings in the City of Chicago. Central Chicago includes 3 of the 77 well-defined community areas of Chicago: the historic business and cultural center of Chicago known as the Loop, as well as the Near North Side and the Near South Side. The combined area is bounded by Lake Michigan on the east, the Chicago River on the west, North Avenue (1600 N.) on the north, and 26th Street (2600 S.) on the south. This