Not sure if this has been posted here, or if this has been discovered. If its already been posted then I will remove this video as soon as I can. Basically was just screwing around in Org with friends trying to get under Org, however we ended up getting under Org, and in doing so under Kalimdor.
Basically, you should be able to explore anywhere not blocked by water, unless your a druid. If you fly under pools of water, you'll be dismounted but you'll be swimming there in space. If your a druid you can jump out of the underground pool and go into flight form.
Theres also a ramp underneath the gates of Orgrimmar which makes a fantastic place to troll. Such methods include Death Grip + Mind Control or Mind Control+ Life Grip+ Mind Control. Or just firing at your opponents. You can also life grip your allies down to where you are. However, any ranged attack can also hit you. Such as charge, or shadowstep. If you aggro any guards they will run down the ramp as if the barrier didn't exist, but those can be easily disposed of with a mind control.
Oh and be careful while death gripping elem shamans, thunderstorm is a bitch on a small platform.
Also this video took me 10 minutes of editing, So don't expect anything out of the ordinary.