I think pretty is subjective. I am not a fan soulless all modern cities. For example I once went to Almere in the Netherlands and I found it quite depressing.

But on the other hand I like cities which keep very old building and pieces of architectures alongside much more modern ones and I think you can always discuss details but Copenhagen is generally a good example of that. Having said that I have not known Copenhagen in the 1960-1970's so maybe older people would tell me it was much prettier back then.