For those truly amazing submissions.
Sometimes Utopias should stay as mere legends.
Old cultures since the dawn of written time have seen pictures in the night sky and asked questions of them. Who they were, where did they come from, and why do they return? The earliest efforts to distinguish these nightly visitors and give them names and meanings dates back to before the Contention of Aborior. Those first observations were different than what is seen today but most still hold true to their original origins.
"Ye thought the orbital penitentiary around Venus was hard ta endure? That place is a vacation spot compared to Davy's Lockdown! If the guard borgs can't find an excuse ta peel the skin off yer bones and the inmates don't use ya for their bettin pool, the pressures o' bein that far beneath the waves will drive ya to the brink, mark my words!"
An underwater prison with a dark past, suitable for any sci-fi, neo-dystopian, or cyber punk setting.
"They said it would bring us a new age of wonder, of exploration, of excitement. I don't think this is what they meant: us scurrying around like rats in our cities of steam and steel, far away from the land and the sun."
An ocean of fine silt, shot through with pillars and islands of ancient stone, this realm would be a thing of harsh beauty were it not for the utterly lifeless nature of it.
"The Tower of Ill Omen!" the old gypsy gasped as she glimpsed the shattered structure at the mountain’s peak.
Trapped forever in the grip of the Sea of Jade, paralyzed by the Great Curse, the Fleet of Nazran has become a hellish prison of eternal torment, and the tomb of adventurers from across the Earth.
A desolate region is almost entirely without normal vegetation. Local plants are able to unroot themselves and crawl along the ground in search of water and fertile soil. The inhabitants fence their crops in to keep them from wandering off and put heavy stone thresholds in the doorways of their huts to keep wayward plants out.
The plants sense by chemical cues, lacking sight or hearing, and tend to avoid herbivores or anything that smells of "dead plants". Characters with horses are likely to be unwelcome among the locals.