I visited Copenhagen back in April 2015, and Amalienborg is a great sight to see when walking between Kastellet and Nyhavn. It's essentially a city square surrounded by the 4 identical facades of the palaces. There's nothing too special about the palaces themselves; the uniqueness simply lies in this beautiful symmetrical layout, but does the layout alone make it World Heritage worthy? It's not an absolutely mindblowing or revolutionary idea, but it's the one aspect that could give the site the OUV it needs to be successfully inscribed, at least in my eyes. In the European region, there are just too many palaces that overshadow Amalienborg, and for now, that's the main idea that will continue to keep the title away from it. However, Amalienborg, to me, is one of the biggest jewels in Copenhagen's crown. Like the other reviews, I'd say that a "Historic Copenhagen" of some sorts that includes Amalienborg would definitely make a better site.