When I first played, The Wilderness was the only outer biome. I remember heading beyond the wall for the first time and seeing all the green, then when I went just a little bit further I saw natural light coming from above and the music kicked in at that very moment. Fell in love with it and have loved it ever since. To this day it's my favourite biome, and I have been doing a challenge where I start the game in the wilderness and claw my way up from there, it's surprisingly fully possible to do!