Avatar: The Last Airbender premiered on Nickelodeon in 2005, and it is considered one of the best cartoons of all time. It may have been marketed towards younger audiences, but Avatar: The Last Airbender tackled dark and serious subject matter, which made it appealing to all ages. The show introduced an interesting power system known as bending. Four of these bending arts involve physical elements, while the fifth deals with energy. The elements are air, fire, water, and earth, and they can all be manipulated through separate martial arts styles. Many humans in Avatar: The Last Airbender are born with the ability to bend, but the original benders had to learn how to bend their respective elements. Some humans learned to bend after being given the power, while others had unlikely teachers.
Source：https://www.cbr.com/avatar-the-last-airbender-bending-origin/
