*nods*

You have to ride a chocobo in order to find the sanctuary. The easiest route is to get one from the forest closest to Trabia Garden. Ride it off the peninsula east of the Garden and into the water. You'll find that there is a path in the ocean you're allowed to take (I believe it is lighter colored). When you reach land, simply ride north. It's up against the cliffs on the northernmost part, shaped like all the others. You can't miss it.