Mapping the Internet

July 16, 2012, 9:00 AM UTC

Unspooling fiber-optic cable that will soon be laid on the bottom of the Atlantic Ocean

FORTUNE — The global economy has arranged itself around a short list of dominant cities, the endpoints for movement of all kinds: goods, people, money, and, increasingly, packets of digital information. These packets — some trillion bytes a second — travel primarily as light through fiber-optic cable. E-mails, images, streaming movies, and money: millions and millions every millisecond.

We take it for granted that the Internet, as much as any city, has a physical reality. Tracing the movement of a packet of information throughout this geography of fiber-optic cables and data centers casts the global economy in a different light. In places, the packets piggyback on existing telecommunications systems, traveling through the same capitals of finance and trade that have long been at the center of things. Elsewhere, the Internet disrupts and reshapes the traditional endpoints of movement. By looking closely at our world’s digital infrastructure, we can discern broader lessons about emerging economies. By understanding how information moves and how networks are constructed, we can see where the Internet is headed, and where the dominant cities of tomorrow might appear.

This story is from the July 23, 2012 issue of Fortune.

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