San Antonio, officially the City of San Antonio, is the seventh most populous city in the United States of America and the second most populous city in the state of Texas, with a population of 1.3 million. It was the fastest growing of the top 10 largest cities in the United States from 2000-2010, and the second from 1990-2000. The city is located in the American Southwest, the south–central part of Texas, and the southwestern corner of an urban region known as the Texas Triangle.San Antonio serves as the seat of Bexar County. The city has characteristics of other western urban centers in which there are sparsely populated areas and a low density rate outside of the city limits. San Antonio is the center of the San Antonio–New Braunfels Metropolitan Statistical Area. Commonly referred to as Greater San Antonio, the metropolitan area has a population of over 2.23 million based on the 2012 U.S. Census estimate, making it the 25th-largest metropolitan area in the United States and third-largest in the state of Texas. Growth along the Interstate 35 and Interstate 10 corridors to the north, west and east make it likely that the metropolitan area will continue to expand.San Antonio was named for Saint Anthony of Padua, whose feast day is on June 13, when a Spanish expedition stopped in the area in 1691. Famous for Spanish missions, the Alamo, the River Walk, the Tower of the Americas, the Alamo Bowl, Marriage Island and host to SeaWorld and Six Flags Fiesta Texas theme parks, the city is visited by approximately 26 million tourists per year according to the San Antonio Convention and Visitors Bureau. The city is home to the four-time NBA champion San Antonio Spurs and the annual San Antonio Stock Show & Rodeo, one of the largest in the country.San Antonio has a strong military presence—it is home to Fort Sam Houston, Lackland Air Force Base, Randolph Air Force Base, Lackland AFB/Kelly Field Annex and Brooks City-Base, with Camp Bullis and Camp Stanley outside the city. Kelly Air Force Base operated out of San Antonio until 2001, when the airfield was transferred over to Lackland AFB and the remaining portions of the base became Port San Antonio, an industrial/business park. San Antonio is home to five Fortune 500 companies and the South Texas Medical Center, the only medical research and care provider in the South Texas region.