It might feel like our communications systems have evolved past the point where we'd need tons of cables, but it couldn't be further from the truth - undersea cables are an integral part of the internet's backbone. But where are they, exactly, and which cable links which hubs? TeleGeography makes a great four-color graphic every year that show exactly that. You can zoom in on the map using your mouse scroll wheel.
(via PopSci - thanks Stanley)