At the Earth's Core

David Innes is a mining heir who funds the experimental "iron mole," a digging vehicle designed by his inventor friend Abner Perry. In a test run, they learn the vehicle cannot be turned, and it tunnels deep into the Earth's crust, emerging into the unknown interior world of Pellucidar. It is inhabited by prehistoric creatures and dominated by the Mahars, a species of flying reptile both intelligent and civilized, but which enslaves and preys on the local stone-age humans. Innes and Perry are captured by the Mahars' ape-like servants and taken with other human captives to the chief Mahar city of Phutra…