Level A3 - "The Hub"
"Inconstant, everchanging, barren. You find tranquility in the silence, yet feel unsafe at the same time. Welcome to the Hub."
Description

The tunnels of The Hub.

Alternate view of The Hub.

An area that can randomly pop up in the tunnels. Level 16's door.
Level A3 acts as a nexus between the majority of the various levels of The Backrooms. It is a long, subterranean, concrete tunnel that houses many scattered steel doors. These doors are the entrances to all the levels of The Backrooms that can be accessed from The Hub. These doors are at inconstant, everchanging positions. To open these doors the respective level key is required. The entire level is illuminated by lights of an orange hue evenly scattered throughout the level, these are known to flicker however. How long exactly cannot be said but it is roughly every 40 minutes.
Level 1 is home to The Hub and has the easiest points of access to it. As a result of this, all level keys can only be found within Level 1. In addition to this. The Hub is home to Level 16. The door to Level 16 is unique from the rest of the doors and The Hub acts as the only access point to Level 16. A level key is still required to open it however. The Mindless Hills are classified as part of the main levels still however as no special circumstances are required for entry, just a key.
The temperature on Level A3 is about -4 degrees celsius. It is also worth noting that level doors can be as close as a meter apart, all the way to miles apart and that each level door does not have it's level number on it, much like the keys. They do, however, have a slight resemblance to the level it will lead you to and the level key will vibrate to the door.
Entrances
Picking up a key in Level 1 will lead you to The Hub if you follow the vibrations, this tends to be a door that opens into The Hub that wouldn't have been there before.
The tunnels of Level 3 can lead here.
The above-ceiling area of Level 0 has a really small chance of you leading here.
A pipe in Level 2 can lead here.
Exits
Using a level key on one of the doors. The key is also not lost when used, you keep it.
Wandering for a days will cause the tunnels to fade into the tunnels of Level 3.