Level 477 is the 487th level of the backrooms less people encounter,
Level 477 - "Infinite Library"
Level 477 of the backrooms is a seemingly infinite library. Level 477 is filled with dangerous entities, such as Entity 477. But is worth coming to because of its many resources. The resources in question, come in backpacks. In this level, you can find things like flasks of almond water, flashlights, batteries, smiler repellent, Jars O' Bright, level compasses, and more.
It is possible to exit the library, but after walking outside in any direction for more than half a mile, you will end up at the front of the library doors. If you happen to be in front of the library doors and then look behind you, you will end up inside the library again. This form of travel can be used to glitch back into level zero, or cause insanity in the mind of whoever uses it.
Level 477's structure is circular and tall, with a grassy courtyard exposed to the sky in the very middle. There is a fountain in the middle of the courtyard, which has Liquid Pain flowing through it.