At the Earth's Core1922

Dr. Abner Perry has invented a high-calibration digging machine affectionately called 'The Iron Mole'. While testing his invention with his financial backer and former student David Innes, the machine malfunctions and the pair end up burrowing deep into the earth to emerge in Pellucidar, a lush underground cavern filled with giant prehistoric creatures. While fleeing one such creature, Dr. Perry and David are captured by strange inhuman soldiers, called Sagoths, and placed with other human slaves, where they meet Ghak and the beautiful Princess Dia. Dia is kidnapped by another human named Hoojah the Sly One, while Dr. Perry, David and the slaves are taken to the city of the Majars, large telepathic bird-like creatures that rule the underground world. While David is sent to repair the walls...