Global cities are not necessarily the biggest in the world, but they are the most economically and politically powerful. Where information and services run 24/7 and the lights dim, but never go out.
With more than half the global population now living in urban areas, mega cities are on the rise. Home to ten million people or more, their skylines are defined by soaring apartment towers and sprawling shanty towns.
By definition, a capital city is one that serves as a Nation's official seat of Government. Invariably they're swarming with visionaries, politicians, academics and activists.
Some of the busiest cities on the planet are port cities. Transcending oceanic boundaries, the great maritime cities of the world bridge countries and continents and unite the global community. They are the world's greatest port cities.
Built on the vestiges of lost empires, many of the ancient metropolises that helped shape the modern world, endure to this day. As religious and cultural centres, they have shaped the ways in which we view the world around us.
Throughout history, there's always been an edge to the map. Braving these frontiers are the world's most remote cities. These remote enclaves serve as gateways to the wild places of the Earth.
