San Francisco, officially the City and County of San Francisco, is the financial, cultural, and transportation center of the San Francisco Bay Area, a region of 7.5 million people which includes San Jose and Oakland. The only consolidated city-county in California, it encompasses a land area of about 46.9 square miles (121 km2) on the northern end of the San Francisco Peninsula, giving it a density of about 17,179 people per square mile (6,632 people per km2). It is the most densely settled large city (population greater than 200,000) in the state of California and the second-most densely populated large city in the United States after New York City. San Francisco is the fourth most populous city in California and the 13th most populous city in the United States, with a population of 805,235 as of the 2010 Census. The San Francisco-Oakland-Fremont metropolitan area has a population of 4,335,391.
In 1776, colonists from Spain established a fort at the Golden Gate and a mission named for Francis of Assisi on the site. The California Gold Rush of 1849 propelled the city into a period of rapid growth, increasing the population in one year from 1,000 to 25,000, and thus transforming it into the largest city on the West Coast at the time. After three-quarters of the city was destroyed by the 1906 earthquake and fire, San Francisco was quickly rebuilt, hosting the Panama-Pacific International Exposition nine years later. During World War II, San Francisco was the port of embarkation for service members shipping out to the Pacific Theater. After the war, the confluence of returning servicemen, massive immigration, liberalizing attitudes, and other factors (Vietnam) led to the Summer of Love and the gay rights movement, cementing San Francisco as a center of liberal activism in the United States.
Today, San Francisco is one of the top tourist destinations in the world, ranking 35th out of the 100 most visited cities worldwide, and is renowned for its chilly summer fog, steep rolling hills, eclectic mix of architecture, and its famous landmarks, including the Golden Gate Bridge, cable cars, and Chinatown. The city is also a principal banking and finance center, and the home to more than 30 international financial institutions, helping to make San Francisco rank 18th in the world's top producing cities, eighth in the United States, and twelfth place in the top twenty global financial centers. http://www.sanfrancisco.travel/