Mount Everest, standing over 29,000 feet above the surface of the sea, is the highest point on earth on which a human can walk. As such, the challenge of reaching this so-called "Third Pole" was a ...

Mount Everest, the highest point on Earth ... magma from deep in the Earth's mantle rises toward the surface and pushes apart two or more plates. Mountains and volcanoes rise along the seam.

The Earth's interior is composed of four layers, three solid and one liquid—not magma but molten metal, nearly as hot as the surface of the sun. The deepest layer is a solid iron ball, about ...