is the land and the improvements - all that is permanently attached to it - either naturally (such as a tree) or by people (such as a building).

Although the land is commonly thought of as being the surface of the earth, it also includes the space above as well as everything below the surface. Theoretically, land extends from the center of the earth, through the surface of the earth and upward to infinity above the earth’s surface. As a practical matter though, the law imposes limitations and recognizes that land consists of the surface of the earth and everything below the surface to a reasonable depth; and everything above the surface to a reasonable height.