Avatar: The Last Airbender takes place in a fantasy world that is home to humans, fantastic animals, and spirits. Human civilization is divided into four nations: the Water Tribes, the Earth Kingdom, the Air Nomads, and the Fire Nation. Each nation has its own natural element, on which it bases its society, and within each nation exist people known as "benders" who have the innate power and ability to control and manipulate the eponymous element of their nation. The show's creators assigned each bending art its own style of martial arts, causing it to inherit the advantages and weaknesses of the martial arts it was assigned. The four types of bending arts are waterbending, earthbending, firebending, and airbending.