Technology within nature
Antenna World (閉塞A, Heisoku A Obstruction A) is a fairly small area that can be reached from the little house in the forest section of Chaotic Buildings.
A tint of green is used here, along with heavy fog. Lots of huge antennas that look very old and unused fill the area. Going east will bring you to a manhole with a ladder that leads to a passage with blue lanters hanging from the ceiling. Going through it takes you to a cute room with a little green thing sitting and bouncing in place. You can rest under the kotatsu in the middle by interacting with it from the lower side.
By not going down the manhole and instead going south you'll see a huge building made of cables that you can enter and it takes you to the Complex.
Nexus → Red Streetlight World → Gray Road → Grass World → Green Neon World → Construction Frame Building → Cog Maze → Forest Pier → Abandoned Factory → Arc de Pillar World → Flooded Ramparts → Mansion → Deserted Pier → Deserted Town → Chaotic Buildings → Antenna World