The Wilderness is a large expanse of curly plants and rocky soil. It is notable for being extremely hard to navigate through all the plants that you see. Wilderness B is the name of a small area that only acts as a connector between the Teleport Maze and FC world A, while the rest of the Wilderness is often known as Wilderness A.
The Wilderness can be entered from two locations: a two-way Aztec arch in the Dark World, and a one-way warp in the Hell section of the Docks. The Toriningen Party, the Aztec Rave Box, and the Barracks Settlement are located relatively near these entrances.
Although most of the areas in the Wilderness are surrounded by thick vegetation, one area is very large (technically bigger than Hell), open and loops like most of the main worlds. It is accessed from the north side of the area west of the Dark World gate. The looping area contains Onsen-san's house, a towel creature that gives you the Towel effect, and an oval of plants. Walking northwards through the oval leads to the red-eyed plants and the sky garden.