Opening sequence

The opening sequence of Avatar: The Last Airbender is displayed at the beginning of every episode.

The sequence
The show opens by showcasing the various bending methods:
 * Water (with Pakku)
 * Earth (with the early design of Toph)
 * Fire (with Azula)
 * Air (unknown, possibly Aang)

It then shows the world map. After that, Katara (narrator) explains the Fire Nation attacked. Following this, Avatar Roku can be seen using all four bending methods. After, Katara and Sokka are seen, then Aang. The title card is shown immediatly after.

Narration
Katara narrates the opening sequence. In the first episode, she states:

"Water. Earth. Fire. Air. My grandmother used to tell me stories about the old days, a time of peace when the Avatar kept balance between the Water Tribes, Earth Kingdom, Fire Nation, and Air Nomads. But that all changed when the Fire Nation attacked. Only the Avatar mastered all four elements. Only he could stop the ruthless firebenders. But when the world needed him most, he vanished. A hundred years have passed and the Fire Nation is nearing victory in the war. Two years ago, my father and the men of my tribe journeyed to the Earth Kingdom to help fight against the Fire Nation, leaving me and my brother to look after our tribe. Some people believe that the Avatar was never reborn into the Air Nomads and that the cycle is broken, but I haven't lost hope. I still believe that somehow the Avatar will return to save the world."

Every episode after that, she says:

"Water. Earth. Fire. Air. Long ago, the 4 nations lived together in harmony. Then everything changed when the Fire Nation attacked. Only the Avatar, master of all 4 elements, could stop them, but when the world needed him most, he vanished. A hundred years passed and my brother and I discovered the new Avatar, an airbender named Aang. And although his airbending skills are great, he still has a lot to learn before he's ready to save anyone. But I believe Aang can save the world."