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
History of Plovdiv tradition. The name "Plovdiv" first appeared around that time and is derived from the city's Thracian name "Pulpudeva" (assumed to be a translation of Philippopolis, from Pulpu = Philippou and deva = city), which was rendered by the Slavs first as "Pəldin" ("Пълдин") or "Pləvdin". Under the rule of the Ottoman Empire, Plovdiv was a focal point for the Bulgarian national movement. During that period Plovdiv was an economic center along with Constantinople, Odrin and Thessaloniki. Due to trade, the emerging Bulgarian bourgeoisie became significant in the society. Trading with Russia and Europe these people experienced political and cultural influences.