Botanical Garden Berlin, with more than 43 ha the greatest botanical garden in Europe. The main tropical greenhouse. The Berlin-Dahlem Botanical Garden and Botanical Museum (German: Botanischer Garten und Botanisches Museum Berlin-Dahlem) is a botanical garden in the German capital city of Berlin, with an area of 43 hectares and around 22,000 different plant species. The garden is located in the Dahlem neighborhood of the borough of Steglitz-Zehlendorf. It was constructed between 1897 and 1910, under the guidance of architect Adolf Engler, in order to present exotic plants returned from German colonies. Today, the garden is part of the Free University of Berlin. The Botanical Museum (Botanisches Museum), with a large herbarium (Herbarium Berolinense) and a large scientific library, is attached to the garden. The complex consists of several buildings and glass-houses, such as the Cactus Pavilion and the Pavilion Victoria (which features a collection of orchids, carnivorous plants and giant white water lily Victoria-Seerosen). The total area of all glass-houses is 6,000 m². The garden's open-air areas, sorted by geographical origin, have a total area of 13 hectares. The garden's arboretum is 14 hectares. The best-known part of the garden is the Great Pavilion (Das Große Tropenhaus). The temperature inside is maintained at 30 °C and air humidity is kept high. Among the many tropical plants it hosts a giant bamboo. In the year 1573, during the time of elector Johann Georg, the first considerable plant assemblage for the enlargement of the domestic stand occurred, because of the farm gardener Desiderius Corbianus at the fruits- and kitchen garden of the Berlin City Palace. Even if that word has not existed at that time, it was that the first „Botanic Garden“ in Berlin. The still existing pleasure garden has developed from it. In 1679 at the Potsdamer Street – in place of the present Heinrich-von-Kleist- park – a hop garden was laid out, which was used, as a purpose of the electoral brewery, as a fruits- and kitchen garden. Carl Ludwig Willdenow has reached, that the garden was assigned in 1809 the Berlin University, which developed worldwide to a recognized „Botanic Garden“ with a scientific character. First stimuli to move the Botanic Garden appeared in 1888, given because of the need, to expand the plantings and to set out an arboretum. Besides many of the old greenhouses would have needed a reconstruction. Added to the unfavourable impacts of the surroundings, which was in the meantime densely developed because of the cities Berlin and Schoeneberg; air pollution and a drawdown harmed the plants. Also the financial aspects of a move to the city center were of importance.