suppermariobroth:

In Super Mario 64, taking the leftmost door on the top floor of the Big Boo’s Haunt foyer leads Mario to a small balcony in the piano room with a window showing the library (top). By default, the camera is positioned in such a way that the library door is obscured by the window’s vertical board. However, going into first-person mode to view the library door reveals that it is missing (bottom). In addition, the rest of the mansion is not rendered, resulting in the door showing the outside of the mansion instead.