San Francisco, officially City and County of San Francisco, is a city that occupies the fourth position of most populated city of the state of California and the 13th of the United States, with a population of approximately 884 382 inhabitants in 2013.
It is the only consolidated city-county of California, and covering a territorial area of 121 km², it has the second highest population density in the country among the cities that exceed 200,000 inhabitants, after New York., financial and transportation of the Bay Area of San Francisco, a metropolitan agglomeration with more than seven million inhabitants, is located in the extreme north of the peninsula of San Francisco, with the Pacific Ocean to the west, the bay of the same name to the east and the entrance of the bay to the north, so it is only connected to the mainland by its southern end. The city of San Francisco was founded by Spanish settlers in 1776. They built a fort in what is now the Golden Gate and founded a mission named in honor of Francisco de Asís San Francisco belonged to the Viceroyalty of New Spain until independence of Mexico in 1821. After the US intervention in Mexico between 1845 and 1848, the city and the rest of Alta California became US territory. In 1848, the California gold rush boosted the city to a period of rapid growth, from 1,000 to 25,000 inhabitants in a year, which made the city the largest on the West Coast at that time.
After having been devastated by the earthquake and fire of 1906, San Francisco was quickly rebuilt, and became the site of the International Exposition of Panama and the Pacific nine years later, during the Second World War, the city was the Port of embarkation of thousands of soldiers leaving for the Pacific War After the war, the confluence of the returning military, massive immigration, liberal attitudes and other factors gave rise to the so-called Summer of Love and the movements in favor of the rights of homosexuals, consolidating San Francisco as a liberal bastion in the United States. The city includes several islands located within the bay, as well as the Farallones, located 43 kilometers from the coast in the Pacific Ocean, communicating with the rest of the country and the world through the San Francisco International Airport. San Francisco is a popular destination for international tourists, being famous for the Golden Gate Bridge, the Transamerica Pyramid building, the streetcars that traverse its steep streets, its modernist and Victorian architecture and its Chinatown, popularly called Chinatown. San Francisco neighborhood is Silicon Valley, a major center for technology and cybernetics research.
The city is also an important financial and banking center, as it is the seat of more than thirty financial institutions, which has helped make San Francisco the eighteenth city in the world by GDP in 2008 and the ninth in the United States. At the moment it is the second American city with better quality of life, only surpassed by Honolulu.