In the 1960s, the first of several master-planned communities that came to define the county were developed, marking the beginning of its transformation from a largely rural county dominated by railroad and oil and gas interests to a major suburban county dominated by service and manufacturing industries. One of the earliest such developments was Quail Valley in Missouri City, whose golf course hosted the Houston Open during the 1973 and 1974 seasons of the PGA Tour. Another was First Colony in Sugar Land, a 9,700-acre development commenced in the 1970s by Houston developer Gerald D. Hines that eventually became the southwest Greater Houston area's main retail hub, anchored by First Colony Mall and Sugar Land Town Square.