This Is the InternetAndrew Blum9/19/11 12:00pmFiled to: InternettelegeographyunderseaCablesExclusiveTop901EditPromoteShare to KinjaToggle Conversation toolsGo to permalinkThe Internet isn't only on your screen. Or behind your couch. Or in Google's data centers. It's also underwater, where fiber-optic cables stretch across oceans and loop around continents.AdvertisementSatellites are like dial-up. Nobody uses them. Undersea cables make the Internet global, with the most sophisticated of them capable of transmitting nearly ten terabits of data per second, compressed through just a handful of fiber-optic strands. There are only hundreds of these cables in waters around the world. And they are all preposterously proportioned, as thin as a garden hose and as long as-actually, nothing. No human construction matches them. They are the longest tubes ever made, and, for the first time ever, there's a truly accurate interactive online map of them.For a decade, Washington DC-based Telegeography has been publishing an undersea cable map. But it's always been on paper, delivered in a cardboard tube, and sold for $250. But starting today (right this second, actually) the company has put its map online, for free, and made it interactive. And rather than scraping data from Wikipedia, Telegeography's Internet cartographers get information the old fashioned way: They ask the cable owners, who happily share the location of their landing stations and the current bandwidth capacity of their systems.AdvertisementBut only to a point. Telegeography has limited how far you can zoom in on the map, keeping the exact locations secret. But is even that much information dangerous? Telegeography's Stephan Beckert doesn't think so. "It's actually more dangerous to not know where the fiber is, because it makes it harder to plan redundancy in networks," he says. For a big network buying wholesale bandwidth across the pond-say a Facebook, Microsoft, or Citibank-the map is an essential tool. For the first time ever, we get to ogle the actual cables that carry the Internet, on the Internet. Andrew Blum (@ajblum) is the author of Tubes: A Journey to the Center of the Internet, coming soon.