The Crust of the earth.
The crust covers the Mantle and the Outer core. Compared to the outer layers, the crust is the thinnest of all. It is about 5KM to over 50KM thick. The crust is the beginning of the whole earth. It is what we almost stand on. The crust is really thin and brittle. It is about 25 miles long. Studies say that the temperature of the crust is 200C.