Undersea cables have made big news in the last few days, ever since several cables were cut last week near Dubai and Alexandria, disrupting Internet service all over the Middle East. (The latest news: It looks like a ship’s anchor sliced one of the cables. Oops!) The accident draws attention to how much our modern lives depend on unseen cables—just three inches thick and buried under sand—that most of us have never even thought about. There are hundreds of thousands of miles of these things snaking under our seas, with even more on the way.

Take a look at this awesome map from the research group Telegeography. It shows more than 120 major undersea cable systems, including the longest one, which clocks in at more than 24,000 miles. The map also includes stats on the amount of data the cables carry (about two terabytes a second under the Atlantic) and a diagram of how they work. Download a free version of to use as wallpaper on your computer—and the next time a cable gets cut, you’ll be able to figure out which countries won’t be receiving any email that day.