Platform game on skyline

With augmented reality and a head mounted display I'd like to be able play a platform game of the skyline I can see, whether that be buildings, trees, mountains, etc. The key technology is being able to detect the skyline. The skyline itself may need to be augmented to make the game possible (e.g. if a jump between building is too great, a platform is put between them) and more interesting. It would be possible to play unique games on the world's famous skylines (e.g. the pyramids, New York, etc).