The BBC has always done a great job with documentaries on technology (remember James Burke's series "Connections").  Now BBC Radio continues the tradition with a fascinating description of how an email travels across the world.  It does extremely well in describing the role submarine fiber optic cables play in delivering Internet traffic.  Check it out at http://www.bbc.co.uk/iplayer/episode/b037j27s/Techno_Odyssey_Cables/#!.