The polar bear indoor retreat area was an essential part of the exhibit. The enclosure consists of rooms, cages, visitor tunnels, employee passages and a kitchen, and was built underground to maximize free space for the polar bears to roam around above ground. The retreat area consists of 4.3 m2, and was designed by architect, DI Peter Hartmann und DI Frank Leopold. The total cost of the project was € 10,700,000, built by Burghautmannschaft Österreich. The builder consulted with Forthuber Doris Tageslichtsysteme to bring daylight underground with the use of Solatube® Daylighting Systems.