1. Crust: This is the outermost layer, the one we live on. It's thin and rocky, with two types:

* Continental crust: Makes up the continents and is thicker.

* Oceanic crust: Forms the ocean floor and is thinner.

2. Mantle: This is the thickest layer, made of hot, dense rock that flows very slowly over millions of years. It's responsible for plate tectonics.

3. Outer Core: This layer is made of liquid iron and nickel. Its movement creates the Earth's magnetic field.

4. Inner Core: This is the Earth's center, made of solid iron and nickel. It's incredibly hot and dense, under immense pressure.