Reference has been made to the existence of such a land within the center of our world dating back to mankind's most ancient texts. The following passage is taken from a recent dissertation discussing the earliest of Hebraic sacred literature:
One of these secrets discussed in the holy Zohar (1, 254a, in the hashmutot) is that our planet Earth is actually hollow and that it has seven layers to it, one inside the other. This view was even postulated by Sir Edmund Haley (discoverer of Haley’s Comet) without him having any knowledge of the Zohar.
According to the Zohar, each layer is separated by a 100-mile high sky; each inner layer of the earth is illuminated by the Earth’s core, which serves as an inner sun. All different types of creatures are said to live in inner Earth, some more human than others, including giants, centaurs and (according to Rabbi Avraham Azulai’s SeferHesed L’Avraham) over 300 other species.
