When you are in the part in Croft Manor when you have to get two blocks on a pad to get acess to both rooms in the middle of the hallway in the sewer bars you will see the Golden Relic, to able to get acess to pick it up you have to get the stone blocks and place them on the stone pad, once you have done that go back to where the Relic is. Then you will see that the are open for you to croach down and pick it up. Once you have done that, Lara's heath bar will rise up and will make hewr stronger so she can take more hits from enimies and not lose as much health but you will also unlock more concept art in the extras menu!