Plovdiv 40,000 objects. The Museum of Natural Science was inaugurated in 1955 in the old edifice of the Plovdiv Municipality built in 1880. It is among the most important museums in the country with rich collections in its Paleontology, Mineralogy, and Botanic sections. There are several rooms for wildlife and it contains Bulgaria's largest freshwater aquarium with 40 fish species. It has a collection of minerals from the Rhodope mountains. The Museum of Aviation was established on 21 September 1991 on the territory of the Krumovo airbase to the southeast of the city. The museum possesses 59 aircraft and indoor and
Plovdiv administrative structured units. According to the "Law for the territorial subdivision of the Capital municipality and the large cities," the territory of Plovdiv Municipality is subdivided into six district administrations with their mayors being appointed following approval by the Municipal Council. In 1969 the villages of Proslav and Komatevo were incorporated into the city. In 1987 the municipalities of Maritsa and Rodopi were separated from Plovdiv which remained their administrative center. In the last several years, the inhabitants from those villages had taken steps to rejoin the "urban" municipality. The city has more than 200 archaeological sites, 30 of which