Avatar The Last Airbender Book 1: Water, Episode 7
This amazing episode of Avatar is called The Winter Solstice: The Spirit World Part 1.
It's truly a great episode and my personal favorite since the Southern Air Temple. This episode introduces the Spirit World, and as Avatar is a bridge between the human and Spirit worlds, in this episode. It's mystical and fascinating and in the end, Aang learns the key information that furthers the plot.
But the highlight of this episode might be the scenes with Iroh. He is given a lot of good character development, and his background is revealed somewhat as it turns out he was a brilliant general for the Fire Nation. Most of all, it shows how he is much more than who he seems as his strength and cunning are revealed in exciting scenes.
I love it a lot. It's a S+ Tier episode and a 10 out of 10.