Louisiana Art Museum in Denmark
If you must see one museum while in Copenhagen, go to the Louisiana. It's about one hour north of the city and you can get there by bus or taxi. The exhibitions and installations are nice but what truly sets this museum apart is the architecture of the building and its setting on the water. Also of note is the exquisitely curated gift shop (we took copious notes of newly discovered designers for the Shop) and the free kids' artistic studios.