Avatar is one of those once-in-a-blue-moon kind of series that is up there with Batman: The Animated Series and Animaniacs as one of the greatest kids' cartoon shows ever. With a wildly colourful world, sprawling mythology, lovable and multidimensional characters, sharp writing and a level of maturity extremely rarely seen in kids' shows, it's a flat-out masterpiece.

The characters grow and change over time in believable and significant ways. The tone always stays consistent. The comedy is laugh-out loud funny without resorting to low-brow humor or adult jokes. The stakes rise every season, yet the show never devolves into brainless action. The writing is very sharp and manages to explore complex and unusual themes like broken families, finding one's way in life, loss, responsibility and escapism not often seen in kids' shows.

The show's main cast consists of well-rounded and believable characters with distinct personalities and flaws, and they all are interesting in their own ways. The series spends a lot of time exploring their pasts and finding out how they turned out the way they are. Some characters don't quite reach this level, but to count that as a major flaw would be just nitpicking.

What separates Avatar even further from the majority of cartoon series is its overarching story with a clear goal and villain defined from almost the word go. Yet this setup never wears itself out during the three seasons, instead taking its time in raising the stakes. Some episodes around two thirds into the series go to really dark places and you'll find yourself thinking "Did that just happen in a kids' show?" The action scenes are very exciting and creative, taking place in places like underground caves, on top of mountains and on zeppelins.

Unfortunately, the show doesn't always use its potential to the fullest, opting mostly for separate one-episode story lines instead of one continuous story. Some of the tension raised at the start of season 3 gets lost as the series goes back to its standard formula after a very striking start. It doesn't really bring the direness of the situation across, but I guess there's only so much darkness you can have in a kids' show.

Recommendation: As one of the best cartoons of all time, The Last Airbender is a magnificent series to viewers of all ages that will stand the test of time. As a kids' show it's a full 10, but due to the sometimes wonky story structure and some wasted potential, overall it's a nine.