Adapted from the Wikipedia entry.
San Francisco, officially designated the City and County of San Francisco, is the cultural, commercial, and financial center of Northern California. It covers an area of about 46.89 square miles, mostly at the north end of the San Francisco Peninsula in the San Francisco Bay Area. San Francisco is one of the most populous cities in California and in the United States, with a population of between 850,000 and 900,000 people--not considering uncounted supernatural residents. The consolidated city-county is also one of the most densely populated counties in the United States, as well as one of the most expensive. It has a per capita personal income of over $110,000 and a particularly high cost of living.
San Francisco was founded on June 29, 1776, when colonists from Spain established Presidio of San Francisco at the Golden Gate and Mission San Francisco de Asís a few miles away, all named for St. Francis of Assisi. The California Gold Rush of 1849 brought rapid growth, making it the largest city on the West Coast at the time. San Francisco became a consolidated city-county in 1856. 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. In World War II, San Francisco was a major port of embarkation for service members shipping out to the Pacific Theater. It then became the birthplace of the United Nations in 1945. After the war, the confluence of returning servicemen, significant immigration, liberalizing attitudes, along with the rise of the "hippie" counterculture, the Sexual Revolution, the Peace Movement growing from opposition to United States involvement in the Vietnam War, and other factors led to the Summer of Love and the gay rights movement, cementing San Francisco as a center of liberal activism in the United States. Politically, the city votes strongly along liberal Democratic Party lines.
A popular tourist destination, San Francisco is known for its cool summers, fog, steep rolling hills, eclectic mix of architecture and landmarks, including the Golden Gate Bridge, cable cars, the former Alcatraz Federal Penitentiary, Fisherman's Wharf, and its Chinatown district. San Francisco is also home to a number of educational and cultural institutions, such as the University of San Francisco (USF), University of California, San Francisco (UCSF), San Francisco State University (SFSU), the De Young Museum, the San Francisco Museum of Modern Art, and the California Academy of Sciences.