"Ever wonder how fault lines, caves, and volcanoes were formed and how people came to live on or next to them? Earth’s Underground Structures uses cutaway illustrations to examine some of the world’s most interesting natural underground structures created by Earth's forces and processes." -- Provided by publisher.

Beneath the surface -- Hang Son Doong -- Mid-Atlantic ridge -- Puerto Princesa underground river -- Sistema Sac Actun -- Alpine fault -- Subterranean sea -- Yellowstone volcano -- West Mata volcano -- Mammoth Cave National Park.