A Global City, also called world city or sometimes alpha city or world center, is a city which is a primary node in the global economic network. The concept comes from geography and urban studies, and the idea that globalization is created, facilitated, and enacted in strategic geographic locales according to a hierarchy of importance to the operation of the global system of finance and trade.
The GaWC examines cities worldwide to narrow them down to a roster of world cities, then ranks these based on their connectivity through four "advanced producer services": accountancy, advertising, banking/finance, and law. The GaWC inventory ranks city economics more heavily than political or cultural factors. Beyond the categories of "Alpha" world cities (with four sub-categories), "Beta" world cities (three sub-categories) and "Gamma" world cities (three sub-categories).
The cities in the 2016 classification are as follows: