A nocturnal house, sometimes called a nocturama, is a building in a zoo or research establishment where nocturnal animals are kept and viewable by the public. The unique feature of buildings of this type is that the lighting within is isolated from the outside and reversed; i.e. it is dark during the day and lit at night. This is to enable visitors and researchers to more conveniently study nocturnal animals during daylight hours.
Internally, a building usually consists of several glass-walled enclosures containing a replica of the animals' normal environments. In the case of burrowing animals, often their tunnels are 'half-glassed' so the animals can be observed while underground.