The Atlas of True Names reveals the etymological roots, or original meanings, of the familiar terms on today's maps of the World and Europe. For instance, where you would normally expect to see the Sahara indicated,the Atlas gives you "Sea of Sand", derived from Arab. es-sahra "desert, sea of sand".
This is very interesting. Most reviewers have mentioned how it makes the real world seem quite Tolkien-esque. My favourite: The Atlantic Ocean apparently means "World Stream of the Mountain of Mountains".
Find out more here. Thanks to Strange Maps for the link.