Beliefs in mysterious underworlds are as old as humanity. But the idea that the earth has a hollow interior was first proposed as a scientific theory in 1691 by

1964 Dr. Bernard says this is the true home of the flying saucers. the epoch-making significance of Adm. Byrd's flight for 1,700 miles into the North Polar open

First English translation of the book that introduced the realm of Hollow Earth. Explores the underground world of Agarttha, sometimes known as Shambhala, a rea