Global cities are epicenters of human activity that help drive the global economy. Their businesses focus mainly on specialized information services, such as financial services, medical services, educational and health services, and tourism. They are also centers of cultural innovation, much of which finds its way into commerce. The global city is a place of very high density in terms of buildings and population. Businesses that thrive in a global city's downtown are information intensive and benefit from the proximity of similar businesses.
Few cities are large and important enough to be considered global cities.
New York, London, and Tokyo are among them. National cities are political, commercial, or cultural capitals. For example, Washington, D.C., is a center for government, Los Angeles for entertainment, Atlanta for media services. Most resemble global cities but operate at a smaller scale or only in selected sectors of commerce. Some national cities, such as Los Angeles, are at the edge of being global cities.