A volcano is a very deep hole in the Earth’s top layer that can let out hot gasses, ash and lava. Many volcanoes are also mountains.

Volcanoes have long shafts that go all the way down through the Earth’s first layer, the crust, to magma in between the crust and the mantle (the Earth’s second layer). It’s so hot there that rocks melt into liquid! This is called magma, which travels up through volcanoes and flows out as lava.

Check out the famous volcanoes below.