Made me think of this:
For those youngsters who never held a game boy in their hands, it's a game called Final Fantasy Adventure, the tree in the background is the Tree of Mana, which was only reachable by using a pendant to reverse the flow of a waterfall (thus implying to me that it was on a floating island in the sky, otherwise a sufficiently good climber could easily reach it, especially considering that magic existed in the world...)
I think they remade this game for the Game Boy Advance and titled it Sword of Mana.