There's a single path that leads out of the Big City (this is not a physical place, remember), and walking it you will find a door. Is an old, plain wood door and is just there, stuck in the middle of a dirt path, but when you walk through it (or around it since there are no walls around it) you will be in the Forest. The Forest is a wild place, and is basically, infinite. The deeper you walk in it, the lesser your rationality will get, until you totally forget yourself. You will become a wild thing with no memories or conscience. Some people choose to stray the Forest on purpose.
You will also become something that can be hunted and eaten, so pay attention.
If you want to eat meat in the Big City, you have to hunt it by yourself in the Forest. Good Luck!

Here, The Stray with Many Names (dog) and Silk Tofu (cat) show us how it works. See? Silk has already lost her ability to walk on her toes and it's just on the other side! Amazing!

Silk by the way, is half wildcat, her father lives in the Forest by his own choice, and she herself has lived between the city and the wild through her whole lives. Don't do it if you're not the least experienced, kids!
(everything related to The Big city is here: https://www.furaffinity.net/gallery...../the-big-city/)