Building Bucket List

     In European travel there have been our own personal bucket lists of things to see. For me one of them was the Dolomite Mountains in the Southern Tyrolean Alps. But, when I think of the list, most of it is comprised of buildings. Here it is (in no specific order): Elizabeth's Tower, The Tower of London, The British Museum, The Abbey at Iona, Balmoral Castle, St. Giles (Edinburgh), The Half Penny Bridge, Newgrange, The Eiffel Tower, Mount Saint Michele, The Louvre, The Pantheon, The Colosseum, The Vatican, The Academia (Florence - Michelangelo's David), The Doge's Palace (Venice), and The Innsbruck Olympic Site. Still to go: Amsterdam (any part of it), The Alhambra, The Bullring in Seville, The Vienna Opera House, Stonehenge,  Oxford University, The tram at Gibraltar, and more. YOUR QUESTION: What would you add to or list as a must see man-made object in Europe.