At the very center of the Earth is a dense and solid inner core of iron and other minerals that is about 1,800 miles (2,896 kilometers) wide. Surrounding the inner core is a liquid (molten) outer core. Surrounding the outer core is the mantle, which makes up the bulk of the interior of the Earth. The mantle is composed of three layers—two outer layers are solid and the inner layer (the asthenosphere) is a layer of rock that is easily moved and shaped.