Last Fertile Region

""Whenever I see a world untouched by war, a world of innocence, a world of lush forests and clear rivers... I really just wanna nuke the crap out of it!""

- Ghost, Starcraft 2

When there's a Dystopia of some kind, especially if it involves machinery, there will usually be one spot in the world that still retains nature and beauty. One area where plants flourish, the water is fine, and in general things are very nice.

The bad guys usually want to get rid of it, either for resource gathering or for the sole purpose of being a douche.

Places like these are often used in a Green Aesop and Gaia's Lament. Related to Hope Sprouts Eternal. Can go hand in hand with The Promised Land when the characters are trying to reach it, and/or converse about it and all its wonders.

Anime and Manga

 * Played with in Phoenix: Resurrection, where the protagonist and his love interest are seen enjoying themselves in a pastoral landscape; however, the protagonist's perceptions have been altered due to a botched resurrection treatment, and this beautiful landscape is actually a run-down factory. (Similarly, the girl is actually a robot who looks only barely human in reality.)
 * In Blue Submarine No. 6, there's an orchard in Antarctica.
 * Nausicaa of the Valley of the Wind, of course.
 * Although it's also sort of a subversion since
 * Green Legend Ran revolves around this for its plot, only instead of a specific region of land, it's also a specific girl with the power to restore the depleted planet back to life.
 * Cephiro in Magic Knight Rayearth 2.
 * Macross Frontier toward the end has.
 * The war between Rome and Helvetia in So Ra No Wo To is over the last fertile territories on Earth, after some mysterious war against... someone turned most of the world into a desert and wrecked the oceans.

Comic Books

 * Averted in the French comic La Bombe, in which a massive pharmaceutical company maintains a vast expanse of Amazonian forest alive on an otherwise dystopian city-planet, because it's actually cheaper to get the various compounds from plants rather than synthesizing them.
 * Avalon in the X-Men epic Age of apocalypse is this. (AND the bad guys are trying to destroy it)

Film

 * Silent Running (1972). All plant life on Earth has been made extinct: the only plants left are in giant greenhouses attached to space freighters. Orders come through to jettison and destroy the domes so the ships can be returned to commercial service.
 * Fern Gully: The Last Rainforest - with a title like that... In this case, Justified because the Big Bad feeds off such evil.
 * Waterworld : The mythical Dry Land...
 * The planet of Pandora in Avatar acts like this on a planet-wide scale for the dissolute, solar-system conquering, machine-driven humans.
 * Ice Pirates
 * Spaceballs
 * At the very end of the film of The Road, birdsong can be heard, implying that the protagonist may have found such a place and that there's hope for the world yet.

Literature

 * In Nineteen Eighty-Four, the countryside pasture that Winston and Julia make love in could count.
 * It was also hardly "untouched". During the war, an atomic bomb had hit the area and more recently, the Party had conducted a large scale deforestation. The reason it was deserted at the time was because all that was left were smaller trees.
 * Children's literature example: Bill Peet's The Wump World—the evil Pollutians take over a Garden Of Eden world and pave it pole to pole, driving the titular Wumps underground, but when they move on, the plants regrow from one little park.
 * Some Star Wars Expanded Universe authors make mention of man-made nature areas on the city planet of Coruscant.
 * In the Second and Last Chronicles of Thomas Covenant Andelain becomes this.
 * Yevgeny Zamyatin's We features a future where most of the Earth's population has been wiped out by war, but a small enclave called the One State remains surrounded by a Green Wall to protect the people from the savagery of the outside world. This is an inversion of the trope, however; the world outside the Green Wall is actually a lush natural reserve, while the One State itself is entirely mechanized and everything in it is made of glass.
 * In The Ear, the Eye, and the Arm Resthaven, "the heart of Africa," is a gigantic nature compound and recreation of life as it was in ancient Africa, in the middle of Zimbabwe, which has been completely industrialized and citified. Resthaven is so utterly protected - few of its inhabitants know of the outside world at all, and even airplanes are expressly forbidden from flying overhead - that it never really runs into danger in the story. Instead, when the lost children enter Resthaven, it's a sign of panic because bureaucracy means they'll never leave.
 * Subverted in Mark Geston's science fiction novel Out of the Mouth of the Dragon, where the only land on Earth whose ecology hasn't been totally destroyed by human activity is a reeking swamp. More or less played straight with the sea, which seems to have miraculously remained fertile, but even that dies in the end.
 * In Pastwatch: The Redemption of Christopher Columbus by Orson Scott Card, . That's how important fertile land is.
 * Interestingly, according to one character,.
 * Interestingly, according to one character,.

Live Action TV

 * Power Rangers RPM has the entire world seemingly overrun by a computer virus and turned into a barren wasteland. The only spot left standing is the domed city of Corinth.
 * The Shallow Valley (the real life Shenandoah Valley) is this in season 5 of The 100. The main conflict is just who gets to control it and live there.

Tabletop Games

 * Thanks to severe overuse of magic, there are very few of them in the world of Athas. And they're usually jealously guarded by cannibal halflings. Some of them, called "The Lands in The Wind", are in (what remains of) the parallel magical dimension, guarded by eladrins.

Video Games

 * In Metal Walker, the Rusted Land is Exactly What It Says on the Tin, a polluted, rusting cesspool. However, there's one spot in the game with trees and plants, aptly named Ever Green.
 * In the fourth Mega Man Zero game, nature is finally returning to Area Zero after a Colony Drop and the Elf Wars ravaged the world. Dr. Weil, the Complete Monster Big Bad, wants to destroy the place not only For the Evulz, but because that's where the humans that escaped him were hiding out.
 * There's a more 'limited' example in Final Fantasy VII... Midgard's use of Mako Reactors, that actually suck The Lifestream right out of the ground, makes it impossible for anything to grow in the area - indeed, there's nothing but dead wasteland for miles around, even once you get outside the city walls. However, in one run-down old church in the slums, in a spot where the old board-floor has rotted through, there lies a small garden, where beautiful, white flowers bloom...
 * Also, while infiltrating Shinra Corporation, the heroes can listen in on a board meeting and learn that.
 * In Wild ARMs 3, there are two fertile regions in what is otherwise a planet-wide desert: a tiny garden and forest powered by the last of the Elw and the region around Yggdrassil.
 * Fallout 3 has Oasis, the only place in the wasteland where trees flourish. The reason that nature flourishes here may be considered nightmare fuel to some, though.
 * Fallout: New Vegas likewise has the valley at the entrance to Vault 22, which is quite lush and verdant in comparison to its surroundings. Unlike in 3, however, the Nightmare Fuel status of the flora from Vault 22 is indisputable.
 * The Command & Conquer series. Tiberium has ravaged much of the world. The GDI occupies the few fertile places left. Both Nod and Scrin wants to bomb the shits out of them.
 * Except the GDI actually made the Blue Zones tiberium-free, although they had to exclude areas that were too far gone (e.g. contaminated water supply).

Western Animation

 * The Great Forest in Sonic Sat AM.
 * The Great Valley in The Land Before Time, although the sequels seem to contrast that.
 * The nesting grounds in Disney's Dinosaur.

Real Life

 * The creation of Demilitarized Zones between countries on the brink of conflict can make for some surprisingly lush nature preserves, set apart from human influence. Particularly, the one between the borders of North and South Korea is one of the most well-preserved temperate habitats in the world, with a number of endangered species within it. Pretty good for a place surrounded by fortified fences, land-mines and sniper towers owned by two countries with quite poor environmental track records.
 * Who would want to build anything there?
 * Ironically the same thing has happened to Chernobyl. The humans that used to inhabit the area were more of a hazard to the wildlife then the residual background radiation.
 * Which sounds almost heartwarming until you realize it could be used as a justification for eco-terrorists to use nuclear weapons. Nothing like a little radiotherapy to cure what ails mother nature...