It is easy to see how great new architectural projects catch the public imagination, particularly with architecturally-minded nations like Denmark. But spare a thought for the grand old buildings that make up the unified, harmonious cityscapes of beautiful cities such as Copenhagen. These houses need to be meticulously maintained, but they also require transformation to remain functional in the modern world. Often, the buildings must stay true to their historical appearance – seemingly unchanged. “We’ve done a good job if you can’t see we’ve been there,” says architect Jens Bertelsen.