The City by the Bay is an obvious candidate for inclusion in any discussion of urban urbanature and perhaps even natural urbanature. San Francisco was located where it is precisely because of the location of the San Francisco Bay, not unlike Baltimore, New Orleans, New York, and numerous urban locations that find themselves near water, surrounded by water, or in some proximity to oceanic, riverine, or otherwise aqueous locations that had a direct impact on the growth of the city, the fame of the city, or some other aspect of its development and history.
San Francisco was founded almost in the twinkling of an eye because of the discovery of that precious metal–gold–and the subsequent California Gold Rush of 1849. Commerace, then finance in the wider sense, and then the American navy all contributed to the rapid growth of our West Coasts most important city in the second half of the 19th century. Then, in 1906, an earthquake and subsequent fire (urbanature anyone?), the likes of which the emerging United States had never seen, devastated the city but also allowed for its rebuilding as a 20th century urban center, the envy of virtually every city west of the Mississippi River (by that time quite a large number of cities).