However, walking is an excellent long-term weight-loss exercise. You can easily walk thousands of miles over decades, because walking has a very low injury risk. How many calories you burn on a one-mile walk depends on your speed and weight.
The thickest layer of the Earth. The Earth can be divided into four main layers: the solid crust on the outside, the mantle, the outer core and the inner core. Out of them, the mantle is the thickest layer, while the crust is the thinnest layer. Artistic depiction of the Earthâs structure. Image via Victoria Museum.
Extending outwards from the core are the mantle and the crust. Earth's mantle extends to a depth of 2,890 km beneath the surface, making it the thickest layer of Earth. This layer is composed of silicate rocks that are rich in iron and magnesium relative to the overlying crust.