This is because the floor and everything you move on is one large 3D model, if you move the camera around and through the wall the game engine will load the default background which is usually the sky (or wierd smoke if you are in the graveyard in OoT) Certain games have very strict collision detection between the camera and the world but this leads to annoying camera problems where you can't look around when in a tight hallway.

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i have FULLY completed and i mean fully completed Oot, Alttp, Oos, Ooa, La, Loz (1st quest), Mc, WW, MM, Aol
and i almost forgot FSA although it really isn't a Zelda game
pending: Loz (2nd quest)

Inuyasha to Kagome: "take it [clothing] off"

Favourite anime:
Naruto, Bleach, InuYasha, FMA, Love Hina, Eureka 7, Ai yori Aoshi +/- ~enishi~