I remember watching a Sex-ed video at school about periods, and it showed a girl swimming. the commentary said that you could only swim with a period if you wore a tampon...
From that day I was scared of going swimming in case my first period started..... I thought you'd have a load of blood trailing behind you if your period started in the pool and everyone would point at you.....
still don't like swimming now.....
A childhood belief about swimming pools

others believed things like this
- I believed that the ladder on the back of a trailer/rv led up to a swimming pool.— marilese
- I used to believe that if you farted while swimming in the pool, it could propel you foward really fast.— Rick
- Up until I was in 3rd grade I believed my bathing cap is what kept me afloat in the swimming pool! Anon
- When I was a kid I used to think the "carpool lane" was an actual pool cars went swimming in— skeez
- I used to think that when you swimming 'Freestyle' was swimming any way you want.Anon
- I used to think that a "pool shark" was an actual shark that lived in a swimming poolAnon