There are a lot of unused data in Pokemon that can only be found in a emulator.
Pokemon Gold and Silver Video RAM
The video RAM contains a lot of funky stuff, mostly glitchy graphics, but there are a few real images too.
To find them, just click Tools, Map Viewer while running a ROM in VisualBoyAdvance, or right click, then Other, then VRAM viewer in BGB. You may have to change the map and char bases if you want to see more interesting pictures.
Screenshots:
It's there because the screen scrolls up and left at the same time, but that much ocean is not needed. It's interesting though.
There's some Japanese in there! I don't know why the block of letters is even there though.
This may be done so for quick loading, but the game seems to scroll to undrawn places as fast as drawn places anyway.
If you look closer the tiles around the Pokemon screen say HI. I don't know why they're there either. It's the same in Pokemon Crystal.
Again, I don't know why it does that, but it must be like Missingno, when it loads random data from some place in the ROM.
Copyright (c) 2003 - 2009 Glitch City Labs Team. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".