I used to believe that swimming pools could only run/be built facing east-west because the water would fall out if it ran north-south. Not sure where that came from, but I know it still comes up when we are with family friends....
A childhood belief about swimming pools

others believed things like this
- I used to think that the pools was a swimming competition.— Matt
- When I was little, I used to think that whatever direction I was facing was north.Anon
- my Dad told me ice rinks were defrosted every evening and turned into swimming pools— neil
- I used to believe that north was always straight ahead. I could never face south, but I knew it was behind me!— Bruces
- I used to believe that the North Pole was the coldest place in the world and the South Pole was the hottest...— Logica
- I used to believe that "car pools" were cars with pools in them, like in the rock videos.— Smart Cookie