See behind Princess's Secret Slide

From Glitches

From the game Super Mario 64 DS for the Nintendo DS.

As Luigi, go to Princess's Secret Slide and slide down until you get out of the walled area and you see the whole map. Now right before the hill, jump and ground-pound. You should stand up. Take a look towards where you just came; you should be able to see through the walls. If you manage to get on top of the area you just came through (try a triple jump), you can see that the other side is the same way.