This image of the Shibuya district of Tokyo is typical of many post-apocalypse artworks. During the seventies and eighties, a lot of SF related art work would feature cities or spacecraft overgrown with plants. Assuming the city had not been destroyed by nuclear attack it appears that our cities will turn green very quickly without us. The History Channel’s Life After People did a good examination of this (see also National Geographic’s Aftermath: Population Zero). Amazing how little of human civilisation will survive even a few hundred years.
Whilst I’m on this Aftermath / Post-Apocalypse theme, have a look at Wired’s 10 Best Apocalyptic Vehicles. For a more RPG orientated take on the end of the world, The Post Apocalyptic Forge has plenty of info on out-of-the-ruins type games. For more films and TV news about the end of the world try Post Apocalyptic Media and QuietEarth, especially the list of 158 Post Apocalyptic movies