Mystery Island?

I enjoy exploring and finding hidden and remote areas in Azeroth. I stumbled upon what appears to be a huge square shaped platform off the coast with winterspring and azshara. Unfortunately it's too far out in the great sea to get a close view. Would really like to know what it is though! Any ideas?

https://i.imgur.com/HyfxcKV.jpg
https://i.imgur.com/kHvT241.jpg

It's nothing, just the end of the map. http://pasteboard.co/Bq4318K.png

It is the end of the map, just a graphical glitch. Just go there using water walking elixirs to check it by yourself.

Well, that is a bit of an anticlimax. Thanks for satisfying my curiosity though :D