Level 7 should not be on the top 10 strangest levels for being hardest to find. Apparently, the guy missed the old man who says "There are secrets where fairies don't live." Let's see. Fairies usually live in ponds. There is a pond without a fairy. Maybe if you do something, then you uncover a secret.
It's really not that hard. You don't need to cheat, as the guy claims. I remember finding it as a little kid back when the game came out. It's common sense and logic.
However, I would put level 7 on the list for a different reason: It's much easier than level 6. I remember doing level 7 on purpose prior to 6 because I found it easier.
ahh how i miss the NES with its vaugue clues on what to do next and extreme crazy difficultly.
Knowing to use a certain item in a certain place from a vague clue you can easily miss make this level hard to find. although of course for some it would be easy or they just got lucky to put two and two together.