Harry Potter

There is a room in Hogwarts that is only visible to those who truly need it. The elves call it the 'Come and Go' room, but those in the know call it the 'Room of Requirements'.

Through generations, multiple people took advantage of this room, be they students or other faculty members. This room helped them with whatever they needed. Scholars, if they knew, would argue till their last breath how this was possible and what ritual, runes, or other forgotten magic was used to create it.

The truth is that the fabled creation of Rowena Ravenclaw was not her work, in a way.

One day, while her co-founders were running errands for creating Hogwarts, she heard a loud thunder. When she went to the site to check, she found a book lying on the ground. When she opened the first page, she found out that this was no ordinary book. On the first page was the description of the book.

She was a scholar, and she knew that this was an incredibly dangerous book. While she used the book in the creation of Hogwarts, she was always careful and used it sparingly.

She used the book to make the world forget about the land Hogwarts was built upon.

She used it to create a grid around the British Isle to help identify the magicals and first bloods.

She used it to make the Hogwarts Registry to find the prospective magical children.

And lastly, she used it to make a room to provide the help one needed.

She dared not use the book to make drastic changes in fear of collapsing reality. She knew that the world runs on cold, hard facts, and her logical mind repulsed the thought of changing that. Had it been Godric or Salazar, they would not have given it a second thought before rewriting reality, but not her.

She knew the power of the book was too great to just leave it lying around, so she hid it in the 'Room of Requirements'. She knew that someone would find it again someday. She just hoped that it would be someone like her.