I often hear noises coming from upstairs. It's strange, though, because there isn't "upstairs."
This is the 3rd floor, the last floor. Above us there's only the roof. Two nights ago I had trouble sleeping. I couldn't calm my thoughts, they were too loud. My thoughts sometimes do that to me. They are stubborn, and don't listen to me when I beg them to stay quiet. Instead of showing any mercy at all, they keep on laughing, playing, making faces at me. Because of them, I stayed up that night. I left the bed, sat on the couch reading The Hobbit, tried to relax my soul with Gandalf's wise words, but not even his magic was powerful enough to put me to sleep.
As I stood there, struggling with myself, I heard those weird noises coming from the ceiling. In fact, I just heard them now. It sounded as if someone was closing a door. There's no doubt that was a door closing. It was the type of noise someone makes when distractedly closing a door behind him / her. Loud, though not necessarily the annoyed type of slamming a door. Just distractedly pushing it back.
What do you think that means?
An invisible world above my building?
A hidden room. A hidden floor! A hidden floor inhabited by invisible people.
A hidden floor inhabited by... ghosts!