Okay so how come we never question where the heck Aang is in the intro? Or what the heck those things behind him are??

As a kid I never questioned it. The intro was just a random opening to another Nickelodeon show I liked and that was it. I never questioned it where is he?? Did it ever come up ever and anything? It's not in the show, Korra, or any of the books. And what are those things he hits? To me it looks like a Dragon or something meditating.