The Red City is an area accessed through Red Streetlight World. To access this area, you need to find the streetlight with one light on its right side.
Features
This place looks like a real city, with a main street, some red streetlights and some red warehouses with no roofs whatsoever. There are 9 warehouses in total. Going right from the main entrance, these warehouses are open:
The 2nd warehouse contains a portal to the Intestines Maze. The 6th warehouse contains a stairwell to the Head Wasteland. The 8th warehouse doesn't contain a portal, but when you enter, a shadow of a man appear being killed by a rope can be seen inside, but it disappears after a while.
If you go left instead of right, it is inverted: 2nd is empty, 4th for Head Wasteland and 8th for Intestines Maze.
The soundtrack for this area is "By音師竹内_626-ryukyu_sasikae". This song uses the same bell sound used in Red Streetlight World's BGM, but only when you're in the street area.