the inner core
inner core
The inner core.
We are not sure whether the core of the earth is solid or not, therefor the innermost layer must be either the core, or the layer next to the core.
potassium
The Earth's inner core is solid metals and the outer core is liquid metals.
The lithosphere
The second layer
The Lithosphere and/or Crust
asthenosphere
the inner core
Thankfully, the solid layer of the Earth's crust is the outer, solid land we live on.