San Francisco International Airport, or SFO, is located 13 miles south of downtown San Francisco, California, near Millbrae and San Bruno in San Mateo County. The second busiest airport in California (after Los Angeles International Airport, or LAX), SFO is also the seventh busiest in the country and the 21st in the world, according to passenger traffic. Virgin America makes its home at SFO, and the airport is also United Airlines’ primary hub for trans-Pacific flights. It’s United’s fifth largest hub in the United States, and it’s even the airline’s maintenance hub.Originally a cow pasture, Mills Field Municipal Airport opened in 1927. Odgen Mill, who leased the pasture for the airport, lent his name to the facility for four years, until 1931, when it became San Francisco Municipal (and later, in 1955, International) Airport. United began running flights from SFO in the 1930s: in 1939, as many as 18 United planes left the airport every weekday. The airport’s international service began in 1946, with the inaugural flight making a hopscotch journey from Sydney, Australia, to Auckland, Fiji, then to Kanton Island, Honolulu, and back to San Francisco, before departing for its final stop in Vancouver, British Columbia. Nonstop flights to Europe were inaugurated by the now defunct Trans World Airlines in 1957.An AirTrain links all of SFO’s terminals, and Bay Area Rapid Transit (BART) connects the airport to San Mateo County, San Francisco. SamTrans bus routes also run from SFO to San Mateo County, San Francisco, and Palo Alto.SFO, perhaps because of its proximity to Los Angeles, appears in several films, chief among them Steve McQueen’s Bullitt, where it serve as the backdrop for the movie’s climax. In the 1973 Dirty Harry film, Magnum Force, Clint Eastwood stops a hijacking at SFO. There was even an eponymous TV show San Francisco International Airport that aired briefly in 1970.If you’re traveling through San Francisco International Airport, look out for a few of the hub’s highlights: Terminal 2 doubles as a museum, with color-changing glass panels and a massive netting sculpture. SFO also boasts the first airport yoga room (a 150-square-foot space that provides mirrors and yoga mats) and restaurants by star chefs like the Food Network’s Cat Cora and local culinary master Tyler Florence.