This is the extension of the Royal Danish Library, and it is a good place to stop by to at least admire. You can sit down on the steps outside, by the canal to take in a moment and enjoy the city. Or you could go inside.
While not all parts of the library are accessible, you can certainly wander around and take the elevators up to check out the way it is designed. Also, beware, it can get really high up here.
Because it is a library, it is also very quiet and good place to get a respite from the rest of the city if you’re getting tired with the hustle and the bustle. Because it is a library, it is hard of hearing friendly.