I was the only child, and when I was about 10 I believed I had a brother who lived in a parallel world. I wrote letters to him, and little stories about how we'd eventually run into each other (even though I had no idea how that could happen).
A childhood belief about imaginary friends

others believed things like this
- I used to believe Sting was my dad in a parallel universe — Jenn Green
- I used to believe that we lived inside of the world. I asked my Dad who lived on the outside of the world. — Pauline
- It never occured to me as a child that teachers lived in houses. I thought they lived at school...— Heidi, Pittsburgh, PA
- I used to believe that in old times the world was grey (black and white, i got the idea from old movies) — Bryce
- Until a few years ago, I believed this was a "doggy dog" world, rather than a "dog-eat-dog" world.— jemima
- when i was a kid i believed i could make things happen just by snapping my fingers like in mary poppins!!Anon