Cologne Zoo was founded in 1860 and is one of the oldest - yet also one of the most modern - zoological gardens. In no other zoo the development of the zoological gardens over the years can be seen so clearly: the buildings starting from the menagerie of the 19th century to the wildlife reserve of the 21st century, from the Moorish-style elephant house and the former birdhouse in the style of a Russian basilica dating back to the 19th century, to the ape island created in a Hagenbeck style and modern natural worlds such as the rain forest.
Since the big cat enclosure opened, designed as a biotope habitat, visitors to Cologne Zoo have been able to view the animals in glass-fronted enclosures without bars. The conversion of the old birdhouse into the South America house for primates shows that tradition and progress must by no means be mutually exclusive. The modern elephant park provides the zoo's elephants with the most space north of the Alps.
Cologne Zoo is also famous for its primate collection. The zoo has around 500 different species of animal from all the world's continents and oceans, including predators as well as the magnificent aquarium with a terrarium and insectarium.
http://www.cologne.de/what-to-do/zoo.html