How do you seamlessly unite the past with the present? Or the historical with the modern? And still not rub purists the wrong way. For that, you don’t need to look further than Haas Haas in Vienna. The mirror facade on Haas Haus I’m sure that would have crossed Hans Hollien’s mind, when he went about designing this masterpiece in 1987. Walking through the historical part of Stephansplatz, you can’t help but notice Haas Haus building, or Haas House. It’s in stark contrast to the other buildings in its surroundings, including Vienna’s oldest architectural masterpieces – St Stephen’s cathedral, which is bang opposite this building. St Stephen’s cathedral Its history…