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

* Crust: The thin, outermost layer of the Earth, composed of rock. It's divided into oceanic crust (thinner and denser) and continental crust (thicker and less dense).

* Mantle: The thickest layer, composed of hot, solid rock that flows very slowly over geological timescales.

* Outer Core: A liquid layer made up mostly of iron and nickel.

* Inner Core: A solid ball of mostly iron and nickel, incredibly hot due to pressure.