Operencia: The Stolen Sun

This one is really easy. Towards the end of the game, you will reach the Tomb of Attila. On the third floor down, you will find a small room that has heat/steam rushing upward. There is a piece of cloth suspended over it that you can take. In a nearby room on the same floor, you can take a similar stream upward to the first level of the tomb to find a hidden chest (and some gold on a ledge). Do this twice (you do not have to snag the gold) and the achievement will pop.