San Francisco is a place.
San Francisco . Located at the north end of the San Francisco Peninsula , San Francisco is about 47.9 sqmi in area , making it the smallest county -- and the only consolidated city-county -- within the state of California . 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 the headquarters of five major banking institutions and various other companies such as Levi Strauss & Co. , Gap Inc. , Salesforce.com , Dropbox , Reddit , Square , Inc. , Dolby , Airbnb , Weebly , Pacific Gas and Electric Company , Yelp , Pinterest , Twitter , Uber , Lyft , Mozilla , Wikimedia Foundation , Craigslist and Weather Underground . The world 's most liveable cities is an informal name given to any list of cities as they rank on an annual survey of living conditions .