 It's 6,371 kilometers to the center of the earth, follow us down, we're going all the way to the heart of the planet. Our world is made of layers, a bit like an onion. And as far as we know, life only exists in the first layer, the crust. In the crust, you'll find the burrows of animals, such as moles and badgers. The deepest are made by Nile crocodiles and can reach depths of 12 meters. The crust is also home to ancient underground cities like El and Gubu in Turkey, an elaborate labyrinth capable of housing 20,000 people, complete with schools and chapels. It is thought to have been built around 370 years BC. The world's deepest mines can go down to around 4 kilometers. South African gold miners have found worms 2 kilometers down, but all life stops before 3 kilometers. Then there's the deepest hole ever drilled, the Cola Superdeep borehole in Russia. Some call it a gateway to hell, with locals claiming to hear the screams of tortured souls. At around 30 to 50 kilometers depth, we reach the next layer, the mantle. It's made of hot rock, which appears solid to us but actually flows very slowly, just a few centimeters a year. These delicate shifts below can give rise to earthquakes above. In the 1960s, a group of scientists attempted to drill into the Earth's mantle. Although unsuccessful, new efforts are afoot with a plan to drill deep below the Indian Ocean. As we descend, the increasing pressure means that atoms become warped and even the most familiar materials behave bizarrely. Crystals change from green to blue to brown, and rock becomes as malleable as plastic. 2,900 kilometers down, we reach the bottom of the mantle. See those two giant blobs? They're the size of continents. Scientists aren't sure how they were formed or what they're made of. They cradle the next layer, the outer core. In Jules Verne's classic novel Journey to the Center of the Earth, Professor Otto Leidenbach encounters an entire underground world replete with prehistoric creatures and the subterranean ocean. While the dinosaurs might have been a bit of a stretch, there is an ocean of sorts. But this one consists of flowing red hot iron and nickel, a sunless sea with its own currents and jet streams. This motion creates a magnetic field that protects the earth from dangerous solar rays. The final layer is known as the inner core. It's 6000 degrees in here. The pressure is so intense that the metals here have crystallized, forming a solid sphere at the very center of our planet. In reality, our little vehicle would have been crushed and melted long ago. And as for our driver, I think she better head back to the surface. It's a long way to go. Good luck!