Since ancient times, fictional worlds have existed below the earth’s surface: populated by mysterious cave dwellers, confusing labyrinths, terrifying monsters, and mysterious cities. In religious storytelling the heavens exist above and Hell, lies below — a place of eternal damnation where sinners suffer everlasting punishment for their wrongdoing. In Dante Alighieri’s Divine Comedy (1320) the poem Inferno, portrays Hell as a gigantic underground space, providing the central character with a route from one side of the earth to the other.

There are many examples of underground worlds in literature: Gabriel Tarde’s Underground Man (1896), presents the reader with a post-apocalyptic story (the Earth destroyed by a new Ice Age, and people escaping beneath the surface to rebuild society); in Niels Klim’s Underground Travels (1741) a smaller, self-contained, planet exists within Earth; Icosaméron (1788) features a subterranean utopia (populated by multicolored, hermaphroditic dwarfs); the satire Improbable Tall-Tale, or Journey to the Center of the Earth (1825) describes underground nations populated by spiders, apes, and humans; Jules Verne’s A Journey to the Center of the Earth (1864) describes a continent sized subterranean world with its own sea, and prehistoric animals; in Lewis Carroll’s Alice’s Adventures in Wonderland (1865) Alice falls down a rabbit hole into a surreal fantasy world of living objects and talking animals; Edward Bulwer-Lytton’s The Coming Race (1871) describes a superhuman subterranean race with telepathic and paranormal powers; Ozma of Oz (1907) details an underground gnome kingdom that also appears in Dorothy and the Wizard in Oz (1908) and Tik-Tok of Oz (1914); Edgar Rice Burroughs’ At the Earth’s Core (1914) takes place in an underground environment filled with prehistoric dinosaurs, stone age people, and a city within a volcanic mountain (protected by a lava waterfall), and the dominant Mahars (a telepathic flying reptile).

Film examples include: The Phantom Empire (1935), a cross genre film serial merging science fiction, musical and the western, The Mole People (1956) features rebellious mole monsters, and a lost ancient civilisation (long ago to expelled from the surface of the earth); Battle Beneath the Earth (1967) sees a Communist Chinese plot to invade America by tunnelling through the earth; and the 1976 film version of Edgar Rice Burroughs’ At the Earth’s Core, which recreates his world for the cinema.

Subterranean environments give storytellers the opportunity to literally drop their characters into an alternate reality: the historical novelty of reliving an ancient civilisation; travelling into a pre-historic world with dinosaurs, exotic fauna and intriguing humanoid cultures of varying sophistication; experiencing the horrors of monsters lurking in darkened caverns; discovering hidden worlds where civilisations have incredible wisdom, or superhuman powers; a common Cold War scenario, people escaping underground to avoid surface radiation after a nuclear war. The subterranean world is a portal to another realm, one where the population may evolve over time, or even genetically mutate — or culturally stagnate to become living historical relics. Today, underground worlds have largely been superseded by interplanetary spacecraft, worm holes, and time travel, which offer greater scope to storytellers and seem more plausible considering today’s sophisticated geological knowledge.

The Matrix trilogy (1999, 2003, 2003) features an underground city called Zion, a safe haven, a retreat, a sanctuary; a place where people can live out their authentically unplugged lives (as as opposed to their illusory dream lives connected to the matrix). In She (1935, remade 1965) the hero discovers a hidden world cut off from civilisation, its culture unchanged from ancient times. This authentic ancient world is ruled by a beautiful queen kept ever-youthful when she bathed in a fountain of cosmic rays. The culture depicted in She is a classic exploration of living history; contemporary explorers discover what is a cultural relic, spiced up with a paranormal twist.

The Time Machine (novel 1898) (film 1960, remade 2002) tells the story of a time traveller who goes into the future, to a horrific post-apocalyptic world where mankind has diverged into passive surface dwellers who are bred as food for beast-like underground dwellers (who are the mutated offspring of people who once inhabited anti-nuclear air-raid shelters). Another post-apocalyptic story, THX-1138 (1971) takes place in a dystopian society, which the audience only discovers is underground in the very last shot.

A similar post-apocalyptic world exists in A Boy and His Dog (1975), a society, living underground, has re-appropriated cultural vestiges that existed before the war, and turned them into a nonsensical, ersatz collage. In Beneath the Planet of the Apes (1970), the hideously mutated remains of humanity have developed telepathic skills, and worship the atomic bomb (longing for a chance to unleash its destructive power). And 12 Monkeys (1995) combines the underground post-apocalyptic silo with a time travel journey.

The Polish black comedy Sex Mission (1984) sees two men, cryogenically frozen, walking up in 2044 in a world where there are no men, only women. The closed-in and claustrophobic society has produced a bizarre, dysfunctional micro-culture. When the men finally escape they discover (much the same as the main character in THX 1138) that the surface world is healthy and normal; the matriarch who dominated the underground world has a comfortable cabin above ground, and enjoys the fresh air, fruit, and sunshine — and she is revealed to be a man in drag.