I used to think that an "in ground pool" was a pool that you had to go down into the ground to get to, like in a cave.
A childhood belief about swimming pools

others believed things like this
- I believed that the Kreepy Crawlie used to clean our pool, would follow me around the pool and eat me. — Mother-of-2
- I thought ground beef was the meat they scraped off the ground at the slaughterhouse. Yuck.Anon
- I used to think that a "pool shark" was an actual shark that lived in a swimming poolAnon
- I used to believe that if you dig a hole in the ground and put pepper in the hole, the ground would sneeze.— Cookie
- If you pee in a pool, the pee disappearsAnon
- I used to believe that your tap water came from the swimmimg pool.— Mimi