It looks more like a simple corridor than a street!
Simple Street (不思議の通路, Fushigi no Tsuro, Passage Wonderland) is an area accessible from Urotsuki's Dream Apartments.
The Simple street is a long, black and white road with 19 doors leading to random different areas in the game, serving as a 'fast-travel' room if you know where you're going.
If you use the Glasses effect here, an arrow will appear in front of one of the doors, and the background will change to the background of the area you are about to enter. If you enter the door with the arrow in front, it transports you to the Day & Night Towers.
How to Cheat the Simple StreetEdit
In actuality, the worlds you enter aren't randomly assigned to each of the doors. Instead, one of the possible worlds is picked at random, and then every door in the area besides the one you entered from (Which is distinguishable from the others by the empty sign above it, all other doors have writing on their signs) will lead to that one area the world picks when you enter it.
However, if you equip the Glasses effect, you can tell which world the Simple Street picks, because the area's black background will change to the chosen world's panorama, including no panorama for the Gray Road. Leaving and reentering the area with the Glasses effect still equipped will draw again for a new world, meaning you can exit and reenter the area as many times as you want until you get the desired area.
NOTE: For some reason, a certain threshold must be met before the Simple Street will begin picking worlds at random. Before then, it will pick Red Streetlight World every time.
Nexus → Urotsuki's Dream Apartments → Simple Street