Kaohsiung City is one of the five special municipalities under the administration of the Republic of China. Located in southern-western Taiwan and facing the Taiwan Strait, it is by area the largest municipality, at 2,947.62 km2, and second most populous with a population of approximately 2.77 million. Since its start at 17th century, Kaohsiung has grown from a small trading village, into the political, economic, transportation, manufacturing, refining, shipbuilding, and industries centers of southern Taiwan. It is a global city with sufficiency as categorized by GaWC in 2012.The Kaohsiung International Airport serving the city is the third largest airport in Taiwan. The Port of Kaohsiung is the largest harbor in Taiwan, but not officially part of Kaohsiung City. The southern terminal of the Sun Yat-sen Freeway is in Kaohsiung. For north-south travel on railway, the city is served by the Taiwan Railway Administration stations of Western Line and Pingtung Line. The Taiwan High Speed Rail also provides fast and frequent railway connection to Taipei City. The Kaohsiung Mass Rapid Transit, the city's subway system, launched in early 2008. Kaohsiung was the host city of the 2009 World Games, a multi-sport event primarily composed of sports not featured in the Olympic Games. The city is also home to the Republic of China Navy fleet headquarters and academy.