Most Pokemon Gameboy/Gameboy Advance Games have some glitch city. Pokemon Gold/Silver/Crystal/Ruby/Sapphire/FireRed/Leafgreen have a glitch city but that needs a cheat device than may distroy your save. bt in Red/Blue and Yellow is another story there is a gameshark-free glitch city in R/B/Y here is how to get it.

Go To The Safari Zone in Fuchsia City Go in

Without Moving into the Safari Zone move out, when he says "Leaving Early" Say no

Save Your Game and reset (Sel+Start+A+B) At the same time

He will welcome you as your were going in say no, you will now be outside

Now walk around in a route not a city some work some don't play around as you can use this cheat again. After 500 Steps it will say "PA Ding Dong Your Time is Up" When you exit the Safari Zone you will be in Glitch City!

Click Here to See Routes That Work