Pellucidar

Traveling 500 miles through the Earth's crust in their "iron mole," David Innes and Professor Perry make the astonishing discovery that the earth' center is hollow and the site of an amazing interior world -- Pellucidar It is at a Stone Age level of development, dominated by chilling reptilian monsters with a high degree of intelligence who communicate through extrasensory means. Evolution is proceeding along different lines in Pellucidar than it did on the Earth' surface, and humans are treated as inferior creatures. Danger and violence are the rule in this land of perpetual noon (the sun is always at the zenith), where time does not exist.
In this second novel of the Pellucidar trilogy (the others are At the Earth's Core and Tanar of Pellucidar), David Innes returns to Pellucidar to seek his lost love, the beautiful Princess Dian, and to fulfill his vow to lead humanity out of the darkness of slavery and subordination. During an epic journey across the strange lands of Pellucidar, Innes has many heart-pounding encounters with strange peoples and savage beasts, often barely escaping with his life.
This book is a prime example of why Burroughs' ritings have enjoyed enormous popularity for a century and are still favorites with young and old alike. Pellucidar is sure to appeal to any reader with a taste for gripping adventure in exotic locales.