Very nice thinking there Besimudo. But think of this, know there is the theory of an Earth Garden and all, but it leaving its place I don't think would make all the cracks in the Crust around the spot where it supposedly is.

Also, I believe if it was only merely there to stop progression, why not just make it a mountain of some sort. I really don't think it was the Lunar Cry, as it is stated in the tutorial that it hit Centra 80 years ago, destroying the continent.

Possibly a Missile and then thinking that a few missiles took out Trabia and part of it is still standing, one wouldn't make a crater THAT big. So really it could be the Lunatic Pandora, but I don't know of anything else.