Our planet's interior is much too deep ... But how good is your knowledge of Earth's inner structure? Find out by taking this quiz. If you need a hint, hit the yellow button.
If you're fascinated by the wonders of our natural world, you'll love updates from the BBC. We'll tell you about new programmes, go behind the scenes and bring you incredible wildlife clips and ...
Mother Earth, Gaia, the third rock from the Sun - whatever you call it, this 4.5 billion-year-old planet is the one that we and all known living creatures call home.