One of the most gorgeous-looking films I've seen this year is City of Ember, the Fox/Walden adaptation of Jeanne Duprau's young-adult fantasy novel about a post-apocalyptic underground city. Although the story is aimed at younger audiences, it's still enjoyable for grown-ups. The movie should be viewed on as large a screen as you can find, giving you the sense that you're this close to the fascinating and decaying city where the story is set.
The movie's prologue lays out the premise clearly. In the future, something goes haywire that causes the end of the world, but fortunately top U.S. scientists have created an underground city to keep a portion of mankind safe. The inhabitants will not be told about the Earth's past, so they won't be traumatized and will assume that their underground city is the only civilization. A box with instructions for returning to the Earth's surface will open in 200 years, which should be time enough for the Earth to be inhabitable again. However, over the course of time the box becomes lost, and after more than two centuries have passed, the city is starting to run out of resources and is falling apart.