Dallas is a major city in Texas and is the largest urban center of the fourth most populous (1.258 million) metropolitan area in the United States. Dallas is the county seat of Dallas County. The city has a total area of 385.8 square miles. The city's prominence arose from its historical importance as a center for the oil and cotton industries, and its position along numerous railroad lines. Dallas developed as a strong industrial and financial center, and a major inland port, due to the convergence of major railroad lines, interstate highways, and the construction of Dallas/Fort Worth International Airport, one of the largest and busiest airports in the world. Dallas was rated as a "beta plus" world city by the Globalization and World Cities Study Group & Network, and was 14th in world rankings of GDP by the Organization for Economic Co-operation and Development. Dallas, like many other cities, was founded along a river. The city was founded at the location of a "white rock crossing" of the Trinity River, where it was easier for wagons to cross the river in the days before ferries or bridges. The lake and surrounding park is a popular destination for boaters, rowers, joggers, and bikers, as well as visitors seeking peaceful respite from the city at the 66-acre. Dallas Arboretum and Botanical Garden, located on the lake's eastern shore. White Rock Creek feeds into White Rock Lake, and then exits on to the Trinity River southeast of downtown Dallas. Trails along White Rock Creek are part of the extensive Dallas County Trails System. The city is well known for its diverse architecture, festival, contemporary arts, and a superior quality of living.