Swimming over New York it's possible!
This is a clever advertising from Ogilvy & Mather for HSBC. The advertising's goal is to raise awareness of the dangers of global warming, so an aerial photo of a city’s skyscrapers has been glued to the base of a swimming pool. The effect of swimming over a city should be awesome!
Nevertheless I have to say that the idea it's not new at all. As you can see in this previous ad campaign