After reading this question, I looked through some One Piece world maps as you can see below and they made me wonder. Where would All Blue even be at? All Blue is supposedly the place where the four seas meet.
The All Blue is a mystical sea of legend, rumoured to be the only place in the world where the North, South, East, and West seas meet.
Since the four seas are separated from each other by the Grand and Red line, how and where would they be able to meet? Where would All Blue be at?
There is even this interactive world map if you would be interested.