Эдгар Райс Берроустың құрған ішкі Жері: Пеллюцидар

Fictional Hollow Earth invented by Edgar Rice Burroughs
a fictional landmass

Pellucidar is a fictional Hollow Earth invented by American writer Edgar Rice Burroughs for a series of action adventure stories. In a crossover event, Tarzan, who was also created by Burroughs, visits Pellucidar. The stories initially involve the adventures of mining heir David Innes and his inventor friend Abner Perry after they use an "iron mole" to burrow 500 miles into the Earth's crust. Later protagonists include indigenous caveman Tanar and additional visitors from the surface world, notably Tarzan, Jason Gridley, and Frederich Wilhelm Eric von Mendeldorf und von Horst.

In Burroughs' concept, the Earth is a hollow shell with Pellucidar as the internal surface of its shell. Pellucidar is accessible to the surface world via a polar tunnel, allowing passage between both the inner and outer worlds through which a rigid airship visits in the fourth book of the series. Although the inner surface of the Earth has a smaller total area than the outer, Pellucidar actually has a greater land area, as its continents mirror the surface world's oceans and its oceans mirror the surface world's continents. The peculiarities of Pellucidar's geography are caused by the concave curvature of its surface. There is no horizon; the further distant an object is, the higher it appears to be, until it is finally lost in a void of atmospheric haze. Pellucidar is lit by a miniature sun suspended at the center of the hollow sphere, so it is perpetually overhead and gives a sensation of eternal noon wherever one is in Pellucidar. The sole exception is a region directly under a tiny geostationary moon of the internal sun. As a result, this region is under a perpetual eclipse and is known as the "Land of Awful Shadow". The moon has its own plant life and (presumably) animal life, and either has its own atmosphere or is simply suspended within Pellucidar's. The miniature sun does not change in brightness and never sets. As a result, with no night or seasonal progression, the natives have little concept of time. The events of the series suggest that time is elastic, passing at different rates in different areas of Pellucidar and varying even in single locations. Also, several characters living in Pellucidar who are originally from the outer world appear to age slowly and exhibit considerable longevity. This is known through their interactions with visitors from the outer world, where time passes at a fixed rate.

Pellucidar is populated by primitive civilizations and prehistoric creatures, including dinosaurs. The region in which Innes and Perry initially find themselves is ruled by the Mahars, a species of intelligent pterosaurs resembling Rhamphorhynchus with vast psychic powers. The Mahars use telekinesis on the neighboring tribes of Stone Age humans as a way of securing their territory. Eventually, two explorers united the tribes in overthrowing the Mahars' reign and establish a human "Empire of Pellucidar" instead. While the Mahars are the dominant species in the Pellucidar novels, these creatures are usually confined to their handful of cities. Before their downfall, the Mahars used Sagoths (a race of gorilla men who speak the same language as Tarzan's Mangani) All of the human inhabitants in Pellucidar share a common worldwide language.