We went to Den Blå Planet, Denmark’s national aquarium on our last day in Copenhagen. The aquarium is situated in Kastrup, Copenhagen, quite close to the airport, and overlooks the narrow sound called the Øresund, which separates Denmark from Sweden. The building is surrounded by a reflection pool and is built in a spiral form inspired by the shape of a vortex. In the larger halls, the high ceilings give a tremendous sense of…