Interesting. I saw today that Delphine Bürkli, the mayor of the 9th arrondissement (which happens to be the one where I live!) suggested that the Paris rooftops should be part of the Unesco World Heritage. I don't know if it will ever happen and if yes, how long it will take, but I tend to think it's a real good idea (of course, I'm a bit biased!). Most Paris rooftops are made of zinc, a sort of metal that does not rust and it gives the skyline a typical looks that can mainly be seen in Paris. I took this photo from one of the rare private rooftop terraces in Paris, in the 9th arrondissement actually!