National Aquarium Denmark, Den Blå Planet is a public aquarium in Denmark. The original aquarium was located in Charlottenlund, but this facility closed in 2012 and most of the animal collection was relocated to the new and much larger aquarium Den Blå Planet in Kastrup, a suburb of Copenhagen. The National Aquarium Denmark, Den Blå Planet opened to the public in March 2013 and is the largest aquarium in Northern Europe.

Kastrup is a suburb of Copenhagen, Denmark, on the east coast of Amager in Tårnby Municipality. It is the site of Copenhagen Airport. In Danish, the airport is often called Kastrup Lufthavn or Københavns Lufthavn, Kastrup.