I have found two 'secret' locations in the game. One is an empty droid factory on Nar Shaddaa. Huge area not on the map, no mobs at all in the area. The other is a large cave system on Voss. This one does have a map, but the entrance is not marked on the world map. Again, there are no mobs inside at all. Both are just big, empty spaces, however they are fully detailed environments. I kind of laugh when people say there isn't any place to explore in this game... then I bring up these two locations and without fail, they've no idea where they are or how to get to them.