Generation II Safari Zone
Contrary to popular belief, there exists a Safari Zone in Pokémon Gold, Silver, and Crystal. A game-altering device must be used to access it, however.
The codes for GameShark that work on the Gold and Silver versions of Pokémon to access the gatehouse are:
010344D0
015045D0
010343D0
The code for Crystal version is:
0101B4DC
0103B5DC
0159B6DC
There also exist codes to directly access the Safari Zone after entering a door. For Pokémon Gold and Silver, these are:
010143D0
010344D0
015145D0
The code for Pokémon Crystal version is:
0101B4DC
0103B5DC
015AB6DC
To get there, just enter any door with the codes on. The player will arrive in the Safari Zone's entry room. At this point, turn off the codes.
Here, one could just go back outside and will find his or herself inside the wall of the closed-down Safari Zone building in Fuchsia City, Kanto.
The player can get back inside by turning back on the codes and entering a building.
But the purpose of this glitch is to get into Safari Zone. So, go through the north doors in the room with the codes off. There will be nobody that the player has to pay.
The player will find him or herself in a somewhat glitched Safari Zone, but most of the tiles are completed. The player can not go back in, but can be on the glitched tiles he or she entered from.
There some normal grass tiles and a lot of tall grass tiles with a pond with no sand around it. Unfortunately, the Safari Zone is rather small and there are no wild Pokémon encounterable in the grass, not even ?????. However some normal pokemon can be encountered in the pond with the use of a super rod but no glitch pokemon.
But this shows us that the programmers originally intended to add the Safari Zone, but possibly replaced it with the National Park.
This is a map the beta Safari Zone: