Uh...let's see....the Spirit temple from OOT. The fact that you have to keep going back and forth from young link to adult link just to get further inside the temple makes it more fun! Well, for me it is.

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"All worlds begin in darkness, and all so end. The heart is no different. Darkness sprouts within it, it grows, consumes it. Such is its nature. In the end, every heart returns to the darkness from whence it came! You see, darkness is the heart's true essence" - Ansem (Kingdom Hearts)