Are you trying to get the clouded mirror? If so, you have to go to the calm lands. Get youself a chocobo to ride. If you go to the save spot where you can buy weapons, you can get a chocobo there when you walk out. Ride the chocobo south. almost to where you leave the map all together. Go slightly to your right and you will see a yellow feather on the ground. Stand on the feather (while on your chocobo) and click the X button. Your chocobo will fly you down into a secret area. Once there, walk to the temple.