Inner Planes is the collective term for a subset of the known planes of existence in the Great Wheel cosmology model and the World Tree cosmology model. The term refers to the placement of the planes at the center of the concentric spheres that made up the Great Wheel model. The Inner Planes were also called the elemental planes because each one was primarily made up of one type of matter. There were six major and twelve minor elemental planes and they could be reached from the Prime Material Plane by traveling through the Ethereal plane. The six major Inner planes were: