Here's a breakdown of the Earth's layers:

* Crust: The outermost layer, thin and solid, is what we live on. It's divided into oceanic crust (under the oceans) and continental crust (what makes up the continents).

* Mantle: The thickest layer, mostly solid but with a semi-molten layer called the asthenosphere.

* Outer Core: Liquid iron and nickel.

* Inner Core: Solid iron and nickel, incredibly hot and dense.