Here's a breakdown of the Earth's structure to give you a better understanding:
* Crust: The outermost layer, thin and rigid, ranging from 5 to 70 kilometers (3 to 43 miles) thick.
* Mantle: The thickest layer, about 2,900 kilometers (1,800 miles) thick, mostly solid but with a partially molten layer called the asthenosphere.
* Outer Core: Liquid iron and nickel, about 2,200 kilometers (1,367 miles) thick.
* Inner Core: Solid iron and nickel, about 1,220 kilometers (758 miles) thick.
So, the inner core lies beneath the crust and the mantle, and within the outer core.