Pellucidar

Pellucidar (1915) is the second book in Edgar Rice Burroughs' Pellucidar series, following At the Earth's Core (1914). While At the Earth's Core introduces the concept of Pellucidar, the vast subterranean world at the center of the Earth, Pellucidar delves deeper into the adventures of its protagonists and explores more of this strange, prehistoric realm. Like the first book, Pellucidar is filled with adventure, romance, and the thrill of exploration as its characters continue their daring journey in an underground world full of savage beasts, ancient tribes, and telepathic reptilian creatures.