North America metropolitan area by population in North America: Greater Mexico City. Canada also breaks into the top ten largest metropolitan areas with the Toronto metropolitan area having six million people. The proximity of cities to each other on the Canada–United States border and Mexico–United States border has led to the rise of international metropolitan areas. These urban agglomerations are observed at their largest and most productive in Detroit–Windsor and San Diego–Tijuana and experience large commercial, economic, and cultural activity. The metropolitan areas are responsible for millions of dollars of trade dependent on international freight. In Detroit-Windsor the Border Transportation Partnership study
Sports in North America North America. Among the major events, the US Open, one of the four Grand Slam events, is held annually at the USTA Billie Jean King National Tennis Center in New York City. The Women's Tennis Association, the principal organizing body of women's professional tennis, is headquartered in St. Petersburg, Florida. Tennis Canada, the Central American & Caribbean Tennis Confederation, and the United States Tennis Association are the regional member organizations of the International Tennis Federation, and help organize various events in their respective areas of North America. Sports in North America There is a wide variety of organized sports in