Stock Photo - San Francisco is a US city, the fourth in California by number of inhabitants (after Los Angeles, San Diego and San Jose), with an estimated population of 884 363 inhabitants in 2017, which places it in twelfth place among the most populated cities of the United States of America and at the same time in second place by population density, behind New York..The city is part of a vast metropolitan area (about 7 million inhabitants, the fifth of the entire country), the San Francisco Bay Area, of which it has always been the economic, financial, cultural and tourist center, even if it has now lost the primacy of population. It is a popular destination for many international tourists, and is known for its cool summer fog, its steep hills, its cultural vibrancy and its architectural eclecticism, which combines Victorian style and modern architecture, for its famous landscapes, including the Golden Gate Bridge, its trams, Alcatraz Island and Chinatown. The University of California, San Francisco is one of the leading biomedical centers in the world, and the hospital is among the leading in the United States. San Francisco (USA), September 24th, 2015.