The Randstad (Dutch pronunciation: [ˈrɑntstɑt]; "Rim" or "Edge" City) is a roughly crescent-shaped conurbation in the central-western Netherlands, consisting primarily of the four largest Dutch cities (Amsterdam, Rotterdam, The Hague and Utrecht); their suburbs, and many towns in between, that all grew and merged into each other, containing almost half the country's population. Among other things, it includes the Port of Rotterdam (the busiest seaport outside of Asia), the Port of Amsterdam (Europe's fourth-busiest seaport), and Amsterdam Airport Schiphol (the busiest airport in Europe by aircraft movements). With a population of approximately 8.4 million people it is one of the largest metropolitan regions in Europe, comparable in population size to the Rhine-Ruhr metropolitan region o