Hi Phyllis, even though the tomb was already explored, the chest containing the object *should* have been there or the item should have been in the chest unless you had the other sim satisfy the same opportunity. If not, then what you could try is saving and going to another world and then go to the location of that tomb and then go to edit town and place a copy of that tomb in the library. Go back to your original save and then go back to the location, go to edit town again, delete the existing tomb and place the new one in its place. However, this may wipe out your sim's opportunity, but it should return eventually. You can do this for all tombs that have been explored already.