Hypothetically, if it were possible to travel to the core of the Earth, one would have to go through five total layers, including the "center of the Earth" as described in Jules Verne's novel. The first and uppermost layer of the Earth is the crust. This is the land we occupy and stand on, and even the deepest caves in the world are just a part of the crust. The second layer of the Earth is the upper mantle. After the upper mantle is the primary mantle itself. Once you've passed the upper mantle and mantle, you would reach the outer core. While you're already technically in the core of the Earth, this is just the outer parts and is still relatively far from the center. The final layer is the inner core. This is the "center of the Earth" that Verne made famous in his classic book.