I was exploring using farsight (a shaman spell kind of like mindvision, only you don't need a target) and found the edge of the world in Kalimdor... I started out in Felwood and was trying to see into Hyjal (the zone, not the instance) and got lost... I found a crashed plane on top of a really tall mountain in Winterspring and then eventually made my way to the edge of the ocean:
Edit: I also found this on wowhead while looking for hidden people and places in Wow.
(https://forum.twguild.org/proxy.php?request=http%3A%2F%2Fupload.wowhead.com%2Fimages%2Fscreenshots%2Fresized%2F69786.jpg&hash=04d22910de3e9369a6c3d9314065fc97c721643f)
http://www.wowhead.com/?npc=19719