Back when Marvel comics first started publishing Spiderman (a month or so after The Fantastic Four) I believed that the superheroes really lived in New York. I dreamed about travelling to New York to see Spidey and talk to Ben Grimm.
A childhood belief about cartoons

others believed things like this
- I used to think that New York was pronounced "Yew Nork"Anon
- That there was an underground tunnel linking New York to San Francisco.— Christophe Chang
- When I was young I thought that York Peppermint Patties were illegal drugs.— Shirley B.
- I used to believe that the "real" Santa Claus was at Macy's in New York City. All the rest were fakes. — Marcia
- I thought the big apple was literally a giant apple in New York Anon
- When I was a child I used to believe that my parents WERE superheroes at night.
Anon