So what does the hollow earth mean in terms of today’s cultural products? The discovery that there were indeed two solid, ice-covered Poles, did not fully hammer in the last nail in the coffin of terra cava literature, or even theory. Its association with New Age philosophy keeps the idea in print, and now, on the web. Publishers and Hollywood have not finished with the possibilities of the world underground either.
Richard Shaver’s I Remember Lemuria was a sensation in the 1930’s, and still prompts discussion among those who believe the tale to be real. Any web search will reveal hundreds of websites dedicated to fringe theories of the hollow earth, including NAZIs, aliens, government conspiracy, spiritual messages and racist messages.
Dr. Raymond Bernard’s 1960’s phenomenon The Hollow Earth remains in print, and espouses the conspiracy theory that the origin of UFOs is from polar openings, similar to Symmesian geography. Arguably, though, Symmes had no intention for his name to be linked to such a preposterous idea, not when his work was based upon research, observation, and reasoning.
Even role playing games have made use of terra cava. In 2006, Exile Game Studio released the Hollow Earth Expedition rpg (role playing game):
“Explore one of the world’s greatest and most dangerous secrets: the Hollow Earth, a savage land filled with dinosaurs, lost civilizations, and ferocious savages! Players take on the roles of two-fisted adventurers, eager academics and intrepid journalists investigating the mysteries of the Hollow Earth. Meanwhile, on the surface, world powers and secret societies vie for control of what may be the most important discovery in all of human history.
Set in the tense and tumultuous 1930s, the action-filled Hollow Earth Expedition is inspired by the literary works of genre giants Edgar Rice Burroughs, Jules Verne, and Sir Arthur Conan Doyle.”
Interestingly, Doyle never wrote about the hollow earth, and the premise of the game seems more derivative of his novel The Lost World, which lends its name to another genre of proto-sf literature similar to terra cava, looking for new world on the surface of the earth.
There is not much modern literature that has attempted to cultivate a hollow earth world, but there are a few recent pieces. Rudy Rucker’s Hollow Earth (1990) is a pastiche of Poe’s work. James Rollins’s Subterranean (1999) discovers a lost race living under the Antarctic ice cap, and more recently, John and Carole Barrowman’s children’s novel Hollow Earth (2012) ‘a supernatural place that holds all the demons, devils and creatures ever imagined.’ The world underground has reclaimed its dark and sinister presence in the Barrowmans’ book, a cultural stereotype that is still more prominent than the happily habitable terra cava of Symmes and the 19th century.
A search of the Internet Movie Database (www.imdb.com) reveals that there are numerous film and television titles under ‘Journey to the Center of the Earth’, the most recent of which was the big budget Brendan Fraser movie in 2008 (which was released in a 3D version) directed by Eric Brevig. Designed as a family film, and forced to contend with modern audiences, the plot and characters do not have very much in common with their namesake by Verne. As Verne was adamant about the accuracy of the science in his novels, he would likely do the proverbial grave-spin if he knew of the existence of this movie.
Another film that is more than thriller than science fiction is James Cameron’s 2011 opus Sanctum, about cave divers in Esa-Ala, New Guinea. Viewers are told ‘It is the last unexplored territory in the world.’ Therein lies the secret to the survival of the terra cava myth long past John C. Symmes and Edgar Rice Burroughs: that we still do not know the whole of what lies beneath the surface of our world.
 ‘The Bone Quill’ book description, <http://www.amazon.co.uk/The-Bone-Quill-John-Barrowman/dp/1780550316/ref=pd_sim_b_4>. Accessed 13/11/2012.