There are three seasons in this series and it is hands-down one of the best children's animated series to come out in a long time. A lot of great messages for kids about forgiveness, hard work, perseverance, and redemption. Along with some great one-liners and silliness. My two boys watch the entire series (and it's sequel of sorts, Legend of Korra) at least 2-3 times per year. Yes, there is some violence, but it is not gratuitous and is mostly rooted in martial arts. I have stolen some of Aang's and Iroh's best lines when talking to my kids about injustice, loyalty, kindness, and persistance. Also, very strong female characters/role models in both this and the Korra series!