Denmark’s Aquarium was founded by civil engineer and contractor Knud Højgaard. It opened for the public in 1939 just four months before the break out of World War II and seven months before the occupation of Denmark. The consequence was closed borders and considerable problems in getting hold of exotic animals to the aquarium. However, through an impressive effort with Danish and home reared fish the aquarium was kept open and active. After the war, the aquarium was in a bad shape, and Knud Højgaard initiated extensive renovations. During the next decades the building went through several modernizations and enlargements.