SemiCylinder
A full cylinder would just be too much.
My own twist on the often cliche world of post apocalypse stuff. A rogue planet (that is to say, one without its own solar system) flew through our own little celestial neighborhood and passed close enough to Earth that its orbit was pulled farther from the sun. Within a matter of months, Earth was mostly frozen over. I am working on a novel in the same topic, and I have a lot of the world, or universe, whatever you want to call it, worked out.
Anyone interested?
Anyone interested?