I'm not sure how many of you are aware of those cases, but I enjoy looking at those out-of-the-way passages to secret stashes of items in a few levels. So far I know only of two areas:
-Graveyards. Not all of them have the layout that have it, but it's generally on the left side behind a treasure gate. It contains two green treasure chests.
-Fire Storm Citadel, 4th level. Right after the last batch of containers before the elevator to the boss, there is one that goes all the way behind a wall to a small area. It contains four red treasure chests.
Has there ever been sightings of different ones? I love when OOO implements secretive things like that, such as spawning the key in Stone Grove.
"secret" but clearly marked on minimap. You cant miss them.