I found the following story especially fascinating having grown up in the New York area. The New York Times Magazine has an article showing how New York City skies could be full of stars if the lights and other distractions were eliminated. There is a slideshow of ten scenes created by French Photographer Thierry Cohen. He blends city scenes with clear starry nights from other locations at the same latitude as the city that have much smaller populations.
You can see his photos at the New York Times site: This Is What the Sky Could Look Like Over New York. His work will be exhibited at the Danziger Gallery in New York in March.