 Long stated that most of the wealthier Houston suburbs are west and north of the central city, while to the southeast the Clear Lake/NASA "[represents] another burgeoning concentration of largely aerospace-related prosperity".Houston, being the largest city in the United States without zoning laws, has grown in an unusual manner.Rather than a single "downtown" as the center of the city's employment, five additional business districts have grown throughout the inner-city—they are Uptown, Texas Medical Center, Greenway Plaza, Westchase, and Greenspoint.