Edgar Rice Burroughs 
Pellucidar 

In 1915, Edgar Rice Burroughs wrote a fantasy series of novel, Pellucidar. In his imagination, Burroughs created a fictional imaginary world, named Pellucidar. It is fictional 'hollow earth' invented by the author, reachable through polar tunnel. Edgar has made the story of inner world, inner sun, primitive civilization etc. realistic and believable. Pellucidar has primitive culture and inhabited by pre-historic creature including dinosaurs. Author depicts David Innes's and Abner Perry's struggle to free humanity from the Mahar tyranny. David Innes come back to Pellucidar in search of his friend Abner, as well as his love, Dian. He deals with the disputes following their initial discovery of Pellucidar, and challenge for the new, human civilisation.