Earth is the central location for the story line. It is the 3rd planet in the solar system and is the only known planet with life in its respective solar system. Its dominant species are Human beings, but it also has many animals and flora.
The planet is ruled by 4 Nations. The Air, Earth, Water, and Fire Nation. All Nations can commant the element of their nation. The Water Nation is located at both the North and South poles and control the water element. They are inuit in nature and culture and are also known for their healing abilities. The Earth Nation is located in the center mass of land and can control the land, and in some cases. Metal. They are known for their elaborate cities. The Fire Nation is located in the far west on a island. They are very militized and are constantly at war with other nations. They are very oriental in culture and are very advanced. They have weapons and ships that run off steam. The Air Nomads, are nomadic in nature but have 4 temples. Each in a remote location, but can easily be reached by a flying bison used by the Air Nomads. The air benders, by their name. Control of course air. They are a peaceful people who are the monks of the planet. But, along with the 4 nations. THere is also 5 villages who also play a important role. They are Ninja villages who are allied with each Nation. There is the Village Hidden in the stone, which is located inside the Earth Nation, the Village Hidden in the Clouds which is like the Air Nomads when it comes to location. They are a very secretive village, much like the Village Hidden by Sound. There is the Village of Bloody Mist. Which is located in the Water Nation, they dont commerce with the Water Benders due to the VIllage being very violent, hence their name and there bad reputation from a lone ninja. Then there is the Village Hidden by Sand, which is located in a desert on the outskirts of the Earth Nation's territory. They mostly keep to them selves. Then the last village, the Village Hidden in the Leaves. Which is also located in the Earth Nation, they are a very diplomatic village and very friendly. The Fire Nation does not have a allied Ninja Village that is known, none have made themselves known.
Most people of Earth can bend elements, it is greatly dependent on what country they are from. Such as you wont see a member of the FIre Nation bending water and vice versa. It is taught by bending masters and is a life long process.
The Ninja's of Earth are known for their many jutsu's and Ninja fighting styles, they are very formidable and are not to be taken lightly. Some Ninja are under demonic influence, such as the Nine Tailed Beast that grants them a massive power boost. There is also other ways a Ninja can increase his power.