San Antonio is best known for its military bases, mostly air force, but it is now home to a multitude of other sectors including oil and gas, healthcare, public sector, financial services and tourism companies, as well as many call centers. Large companies, five Fortune 500s among them, are head quartered in San Antonio. The business center is located in an area that's particularly convenient to get to, being just a mile west of Highway 281, Loop 1604, and close to the international airport.