The document describes Earth's layers from the crust to the core. The crust is the outermost layer and varies in thickness from 5-100km. Below is the mantle, which makes up 67% of Earth's mass and extends to a depth of 2,900km. The mantle is divided into the lithosphere, asthenosphere, and mesosphere. The innermost layer is the core, which is divided into a solid inner core and liquid outer core.